Merge "Added Collision Avoidance."
diff --git a/aos/containers/sized_array.h b/aos/containers/sized_array.h
index 0b8b447..0c13ecc 100644
--- a/aos/containers/sized_array.h
+++ b/aos/containers/sized_array.h
@@ -35,6 +35,21 @@
   SizedArray &operator=(const SizedArray &) = default;
   SizedArray &operator=(SizedArray &&) = default;
 
+  bool operator==(const SizedArray &other) const {
+    if (other.size() != size()) {
+      return false;
+    }
+    for (size_t i = 0; i < size(); ++i) {
+      if (other[i] != (*this)[i]) {
+        return false;
+      }
+    }
+    return true;
+  }
+  bool operator!=(const SizedArray &other) const {
+    return !(*this == other);
+  }
+
   reference at(size_t i) {
     check_index(i);
     return array_.at(i);
diff --git a/aos/util/BUILD b/aos/util/BUILD
index 99ae87d..e712d54 100644
--- a/aos/util/BUILD
+++ b/aos/util/BUILD
@@ -1,5 +1,27 @@
 package(default_visibility = ["//visibility:public"])
 
+cc_library(
+    name = "bitpacking",
+    hdrs = [
+        "bitpacking.h",
+    ],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//third_party/GSL",
+    ],
+)
+
+cc_test(
+    name = "bitpacking_test",
+    srcs = [
+        "bitpacking_test.cc",
+    ],
+    deps = [
+        ":bitpacking",
+        "//aos/testing:googletest",
+    ],
+)
+
 py_library(
     name = "py_trapezoid_profile",
     srcs = [
diff --git a/aos/util/bitpacking.h b/aos/util/bitpacking.h
new file mode 100644
index 0000000..df6ad16
--- /dev/null
+++ b/aos/util/bitpacking.h
@@ -0,0 +1,140 @@
+#ifndef AOS_UTIL_BITPACKING_H_
+#define AOS_UTIL_BITPACKING_H_
+
+#include <assert.h>
+
+#include <type_traits>
+
+#include "third_party/GSL/include/gsl/gsl"
+
+namespace aos {
+
+template <typename Integer>
+typename std::enable_if<std::is_unsigned<Integer>::value, Integer>::type
+MaskOnes(size_t bits) {
+  // Get these edge cases out of the way first, so we can subtract 1 from bits
+  // safely later without getting a negative number.
+  if (bits == 0) {
+    return 0;
+  }
+  if (bits == 1) {
+    return 1;
+  }
+  static constexpr Integer kOne = 1;
+  // Note that we shift at most by bits - 1. bits == sizeof(Integer) * 8 is
+  // valid, and shifting by the width of a type is undefined behavior, so we
+  // need to get a bit fancy to make it all work. Just ORing high_bit in
+  // explicitly at the end makes it work.
+  const Integer high_bit = kOne << (bits - 1);
+  return (high_bit - kOne) | high_bit;
+}
+
+template <typename Integer, size_t bits, size_t offset>
+typename std::enable_if<std::is_unsigned<Integer>::value &&
+                        sizeof(Integer) * 8 >= bits>::type
+PackBits(const Integer value, const gsl::span<char> destination) {
+  assert(static_cast<size_t>(destination.size()) * 8u >= bits + offset);
+  size_t bits_completed = 0;
+  while (bits_completed < bits) {
+    // Which logical bit (through all the bytes) we're writing at.
+    const size_t output_bit = offset + bits_completed;
+    // The lowest-numbered bit in the current byte we're writing to.
+    const size_t output_min_bit = output_bit % 8;
+    // The number of bits we're writing in this byte.
+    const size_t new_bits = std::min(8 - output_min_bit, bits - bits_completed);
+    // The highest-numbered bit in the current byte we're writing to.
+    const size_t output_max_bit = output_min_bit + new_bits;
+    // The new bits to set in the this byte.
+    const uint8_t new_byte_part =
+        (value >> bits_completed) & MaskOnes<Integer>(new_bits);
+    // A mask of bits to keep from the current value of this byte. Start with
+    // just the low ones.
+    uint8_t existing_mask = MaskOnes<uint8_t>(output_min_bit);
+    // And then add in the high bits to keep.
+    existing_mask |= MaskOnes<uint8_t>(std::max<int>(8 - output_max_bit, 0))
+                     << output_max_bit;
+    // The index of the byte we're writing to.
+    const size_t byte_index = output_bit / 8;
+    // The full new value of the current byte. Start with just the existing bits
+    // we're not touching.
+    uint8_t new_byte = destination[byte_index] & existing_mask;
+    // Add in the new part.
+    new_byte |= new_byte_part << output_min_bit;
+    destination[byte_index] = new_byte;
+    bits_completed += new_bits;
+  }
+  assert(bits_completed == bits);
+}
+
+template <typename Integer, size_t bits, size_t offset>
+typename std::enable_if<std::is_unsigned<Integer>::value &&
+                        sizeof(Integer) * 8 >= bits, Integer>::type
+UnpackBits(const gsl::span<const char> source) {
+  Integer result = 0;
+  assert(static_cast<size_t>(source.size()) * 8u >= bits + offset);
+  size_t bits_completed = 0;
+  while (bits_completed < bits) {
+    // Which logical bit (through all the bytes) we're reading at.
+    const size_t input_bit = offset + bits_completed;
+    // The lowest-numbered bit in the current byte we're reading from.
+    const size_t input_min_bit = input_bit % 8;
+    // The number of bits we're reading in this byte.
+    const size_t new_bits = std::min(8 - input_min_bit, bits - bits_completed);
+    // The index of the byte we're reading from.
+    const size_t byte_index = input_bit / 8;
+    // The part of the current byte we're actually reading.
+    const uint8_t new_byte_part =
+        (source[byte_index] >> input_min_bit) & MaskOnes<Integer>(new_bits);
+    result |= static_cast<Integer>(new_byte_part) << bits_completed;
+    bits_completed += new_bits;
+  }
+  assert(bits_completed == bits);
+  return result;
+}
+
+template <int bits>
+uint32_t FloatToIntLinear(float min, float max, float value) {
+  static_assert(bits <= 31, "Only support 32-bit outputs for now");
+  static_assert(bits >= 1, "Bits must be positive");
+  // Start such that value in [0, 1) maps to [0, 2**bits) in the final
+  // result.
+  float result = (value - min) / (max - min);
+  // Multiply so that value is in [0, 2**bits).
+  // Make sure we do the shifting in a 32-bit integer, despite C++'s weird
+  // integer promotions, which is safe because bits is at most 31.
+  result *= static_cast<uint32_t>(UINT32_C(1) << bits);
+  if (result <= 0.0f) {
+    return 0;
+  }
+  const float max_result = MaskOnes<uint32_t>(bits);
+  if (result >= max_result) {
+    return max_result;
+  }
+  return static_cast<uint32_t>(result);
+}
+
+template <int bits>
+float IntToFloatLinear(float min, float max, uint32_t value) {
+  static_assert(bits <= 31, "Only support 32-bit outputs for now");
+  static_assert(bits >= 1, "Bits must be positive");
+  const float max_value = MaskOnes<uint32_t>(bits);
+  if (value > max_value) {
+    value = max_value;
+  }
+  // Start such that result in [0, 2**bits) maps to [min, max) in the final
+  // result.
+  float result = value;
+  // Offset by half a bit so we return a value in the middle of each one.
+  // This causes us to return the middle floating point value which could be
+  // represented by a given integer value.
+  result += 0.5f;
+  // Multiply so that result is in [0, 1).
+  // Make sure we do the shifting in a 32-bit integer, despite C++'s weird
+  // integer promotions, which is safe because bits is at most 31.
+  result *= 1.0f / static_cast<uint32_t>(UINT32_C(1) << bits);
+  return min + result * (max - min);
+}
+
+}  // namespace aos
+
+#endif  // AOS_UTIL_BITPACKING_H_
diff --git a/aos/util/bitpacking_test.cc b/aos/util/bitpacking_test.cc
new file mode 100644
index 0000000..013e911
--- /dev/null
+++ b/aos/util/bitpacking_test.cc
@@ -0,0 +1,387 @@
+#include "aos/util/bitpacking.h"
+
+#include <stdint.h>
+
+#include "gtest/gtest.h"
+
+namespace aos {
+namespace testing {
+
+// Tests MaskOnes with small arguments.
+TEST(MaskOnesTest, Small) {
+  EXPECT_EQ(0u, MaskOnes<uint8_t>(0));
+  EXPECT_EQ(0u, MaskOnes<uint64_t>(0));
+  EXPECT_EQ(1u, MaskOnes<uint8_t>(1));
+  EXPECT_EQ(1u, MaskOnes<uint64_t>(1));
+}
+
+// Tests MaskOnes with large arguments.
+TEST(MaskOnesTest, Large) {
+  EXPECT_EQ(0xFFu, MaskOnes<uint8_t>(8));
+  EXPECT_EQ(0x7Fu, MaskOnes<uint8_t>(7));
+
+  EXPECT_EQ(0xFFu, MaskOnes<uint64_t>(8));
+  EXPECT_EQ(UINT64_C(0xFFFFFFFFFFFFFFFF), MaskOnes<uint64_t>(64));
+  EXPECT_EQ(UINT64_C(0x7FFFFFFFFFFFFFFF), MaskOnes<uint64_t>(63));
+}
+
+// Tests some simple non-edge-case use cases for PackBits.
+TEST(PackBitsTest, Basic) {
+  {
+    std::array<char, 3> buffer{};
+    PackBits<uint8_t, 8, 0>(0, buffer);
+    EXPECT_EQ((std::array<char, 3>{}), buffer);
+    PackBits<uint8_t, 8, 0>(9, buffer);
+    EXPECT_EQ((std::array<char, 3>{{9, 0, 0}}), buffer);
+    PackBits<uint8_t, 8, 8>(7, buffer);
+    EXPECT_EQ((std::array<char, 3>{{9, 7, 0}}), buffer);
+    PackBits<uint8_t, 8, 16>(1, buffer);
+    EXPECT_EQ((std::array<char, 3>{{9, 7, 1}}), buffer);
+  }
+  {
+    std::array<char, 3> buffer{};
+    PackBits<uint16_t, 16, 0>(0xdead, buffer);
+    EXPECT_EQ((std::array<char, 3>{
+                  {static_cast<char>(0xad), static_cast<char>(0xde), 0}}),
+              buffer);
+  }
+  {
+    std::array<char, 3> buffer{};
+    PackBits<uint8_t, 4, 0>(0xd7, buffer);
+    EXPECT_EQ((std::array<char, 3>{{0x7, 0, 0}}), buffer);
+  }
+  {
+    std::array<char, 3> buffer{};
+    PackBits<uint8_t, 4, 4>(0xd7, buffer);
+    EXPECT_EQ((std::array<char, 3>{{0x70, 0, 0}}), buffer);
+  }
+}
+
+// Verifies that PackBits puts bits in an order consistent with increasing
+// offsets.
+TEST(PackBitsTest, Consistency) {
+  {
+    std::array<char, 3> buffer1{};
+    PackBits<uint8_t, 8, 0>(0x80, buffer1);
+    std::array<char, 3> buffer2{};
+    PackBits<uint8_t, 1, 7>(0x1, buffer2);
+    EXPECT_EQ(buffer1, buffer2);
+  }
+  {
+    std::array<char, 1> buffer1{{static_cast<char>(0xFF)}};
+    PackBits<uint8_t, 8, 0>(0x7F, buffer1);
+    std::array<char, 1> buffer2{{static_cast<char>(0xFF)}};
+    PackBits<uint8_t, 1, 7>(0x0, buffer2);
+    EXPECT_EQ(buffer1, buffer2);
+  }
+  {
+    std::array<char, 1> buffer1{};
+    PackBits<uint8_t, 3, 5>(0x7, buffer1);
+    std::array<char, 1> buffer2{};
+    PackBits<uint8_t, 5, 3>(0x3C, buffer2);
+    EXPECT_EQ(buffer1, buffer2);
+  }
+  {
+    std::array<char, 1> buffer1{{static_cast<char>(0xFF)}};
+    PackBits<uint8_t, 3, 5>(0x0, buffer1);
+    std::array<char, 1> buffer2{{static_cast<char>(0xFF)}};
+    PackBits<uint8_t, 5, 3>(0x03, buffer2);
+    EXPECT_EQ(buffer1, buffer2);
+  }
+}
+
+// Tests some simple non-edge-case use cases for UnpackBits.
+TEST(UnpackBitsTest, Basic) {
+  {
+    std::array<char, 3> buffer{};
+    EXPECT_EQ(0u, (UnpackBits<uint8_t, 8, 0>(buffer)));
+    buffer = {{9, 0, 0}};
+    EXPECT_EQ(9u, (UnpackBits<uint8_t, 8, 0>(buffer)));
+    buffer = {{9, 7, 0}};
+    EXPECT_EQ(9u, (UnpackBits<uint8_t, 8, 0>(buffer)));
+    EXPECT_EQ(7u, (UnpackBits<uint8_t, 8, 8>(buffer)));
+    buffer = {{9, 7, 1}};
+    EXPECT_EQ(9u, (UnpackBits<uint8_t, 8, 0>(buffer)));
+    EXPECT_EQ(7u, (UnpackBits<uint8_t, 8, 8>(buffer)));
+    EXPECT_EQ(1u, (UnpackBits<uint8_t, 8, 16>(buffer)));
+  }
+  {
+    const std::array<char, 3> buffer = {
+        {static_cast<char>(0xad), static_cast<char>(0xde), 0}};
+    EXPECT_EQ(0xdead, (UnpackBits<uint16_t, 16, 0>(buffer)));
+  }
+  {
+    const std::array<char, 3> buffer = {{static_cast<char>(0xF7), 0, 0}};
+    EXPECT_EQ(7u, (UnpackBits<uint8_t, 4, 0>(buffer)));
+  }
+  {
+    const std::array<char, 3> buffer = {{static_cast<char>(0x7F), 0, 0}};
+    EXPECT_EQ(7u, (UnpackBits<uint8_t, 4, 4>(buffer)));
+  }
+}
+
+// Tests PackBits split across multiple bytes.
+TEST(PackBitsTest, AcrossBytes) {
+  {
+    std::array<char, 2> buffer{};
+    PackBits<uint8_t, 8, 7>(0xFF, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0x80), static_cast<char>(0x7F)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{};
+    PackBits<uint8_t, 8, 6>(0xFF, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xC0), static_cast<char>(0x3F)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{};
+    PackBits<uint8_t, 8, 5>(0xFF, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xE0), static_cast<char>(0x1F)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{};
+    PackBits<uint8_t, 8, 4>(0xFF, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xF0), static_cast<char>(0x0F)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{};
+    PackBits<uint8_t, 8, 3>(0xFF, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xF8), static_cast<char>(0x07)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{};
+    PackBits<uint8_t, 8, 2>(0xFF, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xFC), static_cast<char>(0x03)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{};
+    PackBits<uint8_t, 8, 1>(0xFF, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xFE), static_cast<char>(0x01)}}),
+              buffer);
+  }
+}
+
+// Tests UnpackBits split across multiple bytes.
+TEST(UnpackBitsTest, AcrossBytes) {
+  {
+    const std::array<char, 2> buffer = {
+        {static_cast<char>(0x80), static_cast<char>(0x7F)}};
+    EXPECT_EQ(0xFFu, (UnpackBits<uint8_t, 8, 7>(buffer)));
+  }
+  {
+    const std::array<char, 2> buffer = {
+        {static_cast<char>(0xC0), static_cast<char>(0x3F)}};
+    EXPECT_EQ(0xFFu, (UnpackBits<uint8_t, 8, 6>(buffer)));
+  }
+  {
+    const std::array<char, 2> buffer = {
+        {static_cast<char>(0xE0), static_cast<char>(0x1F)}};
+    EXPECT_EQ(0xFFu, (UnpackBits<uint8_t, 8, 5>(buffer)));
+  }
+  {
+    const std::array<char, 2> buffer = {
+        {static_cast<char>(0xF0), static_cast<char>(0x0F)}};
+    EXPECT_EQ(0xFFu, (UnpackBits<uint8_t, 8, 4>(buffer)));
+  }
+  {
+    const std::array<char, 2> buffer = {
+        {static_cast<char>(0xF8), static_cast<char>(0x07)}};
+    EXPECT_EQ(0xFFu, (UnpackBits<uint8_t, 8, 3>(buffer)));
+  }
+  {
+    const std::array<char, 2> buffer = {
+        {static_cast<char>(0xFC), static_cast<char>(0x03)}};
+    EXPECT_EQ(0xFFu, (UnpackBits<uint8_t, 8, 2>(buffer)));
+  }
+  {
+    const std::array<char, 2> buffer = {
+        {static_cast<char>(0xFE), static_cast<char>(0x01)}};
+    EXPECT_EQ(0xFFu, (UnpackBits<uint8_t, 8, 1>(buffer)));
+  }
+}
+
+// Verifies that PackBits avoids touching adjacent bits.
+TEST(PackBitsTest, AdjacentBits) {
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint8_t, 1, 0>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xFE), static_cast<char>(0xFF)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint8_t, 7, 0>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0x80), static_cast<char>(0xFF)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint8_t, 8, 0>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0x00), static_cast<char>(0xFF)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint16_t, 9, 0>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0x00), static_cast<char>(0xFE)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint16_t, 14, 0>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0x00), static_cast<char>(0xC0)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint16_t, 15, 0>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0x00), static_cast<char>(0x80)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint16_t, 15, 1>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0x01), static_cast<char>(0x00)}}),
+              buffer);
+  }
+  {
+    std::array<char, 2> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint16_t, 6, 8>(0, buffer);
+    EXPECT_EQ((std::array<char, 2>{
+                  {static_cast<char>(0xFF), static_cast<char>(0xC0)}}),
+              buffer);
+  }
+  {
+    std::array<char, 4> buffer{
+        {static_cast<char>(0xFF), static_cast<char>(0xFF),
+         static_cast<char>(0xFF), static_cast<char>(0xFF)}};
+    PackBits<uint16_t, 6, 24>(0, buffer);
+    EXPECT_EQ((std::array<char, 4>{
+                  {static_cast<char>(0xFF), static_cast<char>(0xFF),
+                   static_cast<char>(0xFF), static_cast<char>(0xC0)}}),
+              buffer);
+  }
+}
+
+// Tests FloatToIntLinear with values near or outside of its boundaries.
+TEST(FloatToIntLinearTest, OutOfBounds) {
+  EXPECT_EQ(0u, (FloatToIntLinear<1>(0.0f, 1.0f, 0.0f)));
+  EXPECT_EQ(0u, (FloatToIntLinear<1>(0.0f, 1.0f, -0.1f)));
+  EXPECT_EQ(0u, (FloatToIntLinear<1>(0.0f, 1.0f, -1.0f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(0.0f, 1.0f, 1.0f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(0.0f, 1.0f, 1.1f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(0.0f, 1.0f, 2.0f)));
+
+  EXPECT_EQ(0u, (FloatToIntLinear<1>(0.0f, 4.0f, 0.0f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(0.0f, 4.0f, 4.0f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(0.0f, 4.0f, 10.0f)));
+
+  EXPECT_EQ(0u, (FloatToIntLinear<3>(0.0f, 4.0f, 0.0f)));
+  EXPECT_EQ(0u, (FloatToIntLinear<3>(0.0f, 4.0f, -100.0f)));
+  EXPECT_EQ(7u, (FloatToIntLinear<3>(0.0f, 4.0f, 4.0f)));
+  EXPECT_EQ(7u, (FloatToIntLinear<3>(0.0f, 4.0f, 4.01f)));
+
+  EXPECT_EQ(0u, (FloatToIntLinear<3>(-3.0f, 5.0f, -3.0f)));
+  EXPECT_EQ(0u, (FloatToIntLinear<3>(-3.0f, 5.0f, -3.1f)));
+  EXPECT_EQ(7u, (FloatToIntLinear<3>(-3.0f, 5.0f, 5.0f)));
+  EXPECT_EQ(7u, (FloatToIntLinear<3>(-3.0f, 5.0f, 5.1f)));
+}
+
+// Tests that FloatToIntLinear rounds correctly at the boundaries between output
+// values.
+TEST(FloatToIntLinearTest, Rounding) {
+  EXPECT_EQ(0u, (FloatToIntLinear<1>(0.0f, 1.0f, 0.49f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(0.0f, 1.0f, 0.51f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(-1.0f, 0.0f, -0.49f)));
+  EXPECT_EQ(0u, (FloatToIntLinear<1>(-1.0f, 0.0f, -0.51f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<1>(-1.0f, 1.0f, 0.01f)));
+  EXPECT_EQ(0u, (FloatToIntLinear<1>(-1.0f, 1.0f, -0.01f)));
+
+  EXPECT_EQ(0u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.124f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.126f)));
+  EXPECT_EQ(1u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.249f)));
+  EXPECT_EQ(2u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.251f)));
+  EXPECT_EQ(2u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.374f)));
+  EXPECT_EQ(3u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.376f)));
+  EXPECT_EQ(3u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.499f)));
+  EXPECT_EQ(4u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.501f)));
+  EXPECT_EQ(4u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.624f)));
+  EXPECT_EQ(5u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.626f)));
+  EXPECT_EQ(5u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.749f)));
+  EXPECT_EQ(6u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.751f)));
+  EXPECT_EQ(6u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.874f)));
+  EXPECT_EQ(7u, (FloatToIntLinear<3>(0.0f, 1.0f, 0.876f)));
+}
+
+// Tests IntToFloatLinear with values near or outside of its boundaries.
+TEST(IntToFloatLinearTest, OutOfBounds) {
+  EXPECT_EQ(0.25f, (IntToFloatLinear<1>(0.0f, 1.0f, 0)));
+  EXPECT_EQ(0.75f, (IntToFloatLinear<1>(0.0f, 1.0f, 1)));
+  EXPECT_EQ(0.75f, (IntToFloatLinear<1>(0.0f, 1.0f, 2)));
+  EXPECT_EQ(0.75f, (IntToFloatLinear<1>(0.0f, 1.0f, 3)));
+
+  EXPECT_EQ(1.0f, (IntToFloatLinear<1>(0.0f, 4.0f, 0)));
+  EXPECT_EQ(3.0f, (IntToFloatLinear<1>(0.0f, 4.0f, 1)));
+
+  EXPECT_EQ(0.0625f, (IntToFloatLinear<3>(0.0f, 1.0f, 0)));
+  EXPECT_EQ(0.9375f, (IntToFloatLinear<3>(0.0f, 1.0f, 7)));
+  EXPECT_EQ(0.9375f, (IntToFloatLinear<3>(0.0f, 1.0f, 8)));
+}
+
+// Tests IntToFloatLinear with some specific values which are easy to calculate
+// by hand.
+TEST(IntToFloatLinearTest, Values) {
+  EXPECT_EQ(0.125f, (IntToFloatLinear<2>(0.0f, 1.0f, 0)));
+  EXPECT_EQ(0.375f, (IntToFloatLinear<2>(0.0f, 1.0f, 1)));
+  EXPECT_EQ(0.625f, (IntToFloatLinear<2>(0.0f, 1.0f, 2)));
+  EXPECT_EQ(0.875f, (IntToFloatLinear<2>(0.0f, 1.0f, 3)));
+
+  EXPECT_EQ(0.0625f, (IntToFloatLinear<3>(0.0f, 1.0f, 0)));
+  EXPECT_EQ(0.1875f, (IntToFloatLinear<3>(0.0f, 1.0f, 1)));
+  EXPECT_EQ(0.3125f, (IntToFloatLinear<3>(0.0f, 1.0f, 2)));
+  EXPECT_EQ(0.4375f, (IntToFloatLinear<3>(0.0f, 1.0f, 3)));
+  EXPECT_EQ(0.5625f, (IntToFloatLinear<3>(0.0f, 1.0f, 4)));
+  EXPECT_EQ(0.6875f, (IntToFloatLinear<3>(0.0f, 1.0f, 5)));
+  EXPECT_EQ(0.8125f, (IntToFloatLinear<3>(0.0f, 1.0f, 6)));
+  EXPECT_EQ(0.9375f, (IntToFloatLinear<3>(0.0f, 1.0f, 7)));
+
+  EXPECT_EQ(-0.875f, (IntToFloatLinear<2>(-1.0f, 0.0f, 0)));
+  EXPECT_EQ(-0.625f, (IntToFloatLinear<2>(-1.0f, 0.0f, 1)));
+  EXPECT_EQ(-0.375f, (IntToFloatLinear<2>(-1.0f, 0.0f, 2)));
+  EXPECT_EQ(-0.125f, (IntToFloatLinear<2>(-1.0f, 0.0f, 3)));
+
+  EXPECT_EQ(-0.75f, (IntToFloatLinear<2>(-1.0f, 1.0f, 0)));
+  EXPECT_EQ(-0.25f, (IntToFloatLinear<2>(-1.0f, 1.0f, 1)));
+  EXPECT_EQ(0.25f, (IntToFloatLinear<2>(-1.0f, 1.0f, 2)));
+  EXPECT_EQ(0.75f, (IntToFloatLinear<2>(-1.0f, 1.0f, 3)));
+}
+
+}  // namespace testing
+}  // namespace aos
diff --git a/frc971/control_loops/BUILD b/frc971/control_loops/BUILD
index d12d3da..5871a29 100644
--- a/frc971/control_loops/BUILD
+++ b/frc971/control_loops/BUILD
@@ -341,3 +341,72 @@
         "//aos/testing:googletest",
     ],
 )
+
+cc_library(
+    name = "capped_test_plant",
+    testonly = True,
+    srcs = [
+        "capped_test_plant.cc",
+    ],
+    hdrs = [
+        "capped_test_plant.h",
+    ],
+    deps = [
+        ":state_feedback_loop",
+        "//aos/testing:googletest",
+    ],
+)
+
+cc_library(
+    name = "static_zeroing_single_dof_profiled_subsystem",
+    hdrs = [
+        "static_zeroing_single_dof_profiled_subsystem.h",
+    ],
+    deps = [
+        "//frc971/control_loops:profiled_subsystem",
+    ],
+)
+
+genrule(
+    name = "genrule_static_zeroing_single_dof_profiled_subsystem_test",
+    outs = [
+        "static_zeroing_single_dof_profiled_subsystem_test_plant.h",
+        "static_zeroing_single_dof_profiled_subsystem_test_plant.cc",
+        "static_zeroing_single_dof_profiled_subsystem_test_integral_plant.h",
+        "static_zeroing_single_dof_profiled_subsystem_test_integral_plant.cc",
+    ],
+    cmd = "$(location //frc971/control_loops/python:static_zeroing_single_dof_profiled_subsystem_test) $(OUTS)",
+    tools = [
+        "//frc971/control_loops/python:static_zeroing_single_dof_profiled_subsystem_test",
+    ],
+)
+
+cc_library(
+    name = "static_zeroing_single_dof_profiled_subsystem_test_plants",
+    srcs = [
+        "static_zeroing_single_dof_profiled_subsystem_test_integral_plant.cc",
+        "static_zeroing_single_dof_profiled_subsystem_test_plant.cc",
+    ],
+    hdrs = [
+        "static_zeroing_single_dof_profiled_subsystem_test_integral_plant.h",
+        "static_zeroing_single_dof_profiled_subsystem_test_plant.h",
+    ],
+    deps = [
+        ":state_feedback_loop",
+    ],
+)
+
+cc_test(
+    name = "static_zeroing_single_dof_profiled_subsystem_test",
+    srcs = [
+        "static_zeroing_single_dof_profiled_subsystem_test.cc",
+    ],
+    deps = [
+        ":capped_test_plant",
+        ":position_sensor_sim",
+        ":static_zeroing_single_dof_profiled_subsystem",
+        ":static_zeroing_single_dof_profiled_subsystem_test_plants",
+        "//aos/controls:control_loop_test",
+        "//aos/testing:googletest",
+    ],
+)
diff --git a/frc971/control_loops/capped_test_plant.cc b/frc971/control_loops/capped_test_plant.cc
new file mode 100644
index 0000000..8f32551
--- /dev/null
+++ b/frc971/control_loops/capped_test_plant.cc
@@ -0,0 +1 @@
+#include "frc971/control_loops/capped_test_plant.h"
\ No newline at end of file
diff --git a/frc971/control_loops/capped_test_plant.h b/frc971/control_loops/capped_test_plant.h
new file mode 100644
index 0000000..65bc7cc
--- /dev/null
+++ b/frc971/control_loops/capped_test_plant.h
@@ -0,0 +1,32 @@
+#ifndef FRC971_CONTROL_LOOPS_CAPPED_TEST_PLANT_H_
+#define FRC971_CONTROL_LOOPS_CAPPED_TEST_PLANT_H_
+
+#include "frc971/control_loops/state_feedback_loop.h"
+#include "gtest/gtest.h"
+
+namespace frc971 {
+namespace control_loops {
+
+// Basic state feedback plant for use in tests.
+class CappedTestPlant : public StateFeedbackPlant<2, 1, 1> {
+ public:
+  explicit CappedTestPlant(StateFeedbackPlant<2, 1, 1> &&other)
+      : StateFeedbackPlant<2, 1, 1>(::std::move(other)) {}
+
+  void CheckU(const ::Eigen::Matrix<double, 1, 1> &U) override {
+    EXPECT_LE(U(0, 0), U_max(0, 0) + 0.00001 + voltage_offset_);
+    EXPECT_GE(U(0, 0), U_min(0, 0) - 0.00001 + voltage_offset_);
+  }
+
+  double voltage_offset() const { return voltage_offset_; }
+  void set_voltage_offset(double voltage_offset) {
+    voltage_offset_ = voltage_offset;
+  }
+
+ private:
+  double voltage_offset_ = 0.0;
+};
+
+}  // namespace frc971
+}  // namespace control_loops
+#endif  // FRC971_CONTROL_LOOPS_CAPPED_TEST_PLANT_H_
\ No newline at end of file
diff --git a/frc971/control_loops/drivetrain/trajectory.cc b/frc971/control_loops/drivetrain/trajectory.cc
index 64b4612..c9582e6 100644
--- a/frc971/control_loops/drivetrain/trajectory.cc
+++ b/frc971/control_loops/drivetrain/trajectory.cc
@@ -362,31 +362,32 @@
   return result;
 }
 
-::std::vector<::Eigen::Matrix<double, 3, 1>> Trajectory::PlanXVA(
-    ::std::chrono::nanoseconds dt) {
+::Eigen::Matrix<double, 3, 1> Trajectory::GetNextXVA(
+    ::std::chrono::nanoseconds dt, ::Eigen::Matrix<double, 2, 1> *state) {
   double dt_float =
       ::std::chrono::duration_cast<::std::chrono::duration<double>>(dt).count();
-  double t = 0.0;
-  ::Eigen::Matrix<double, 2, 1> state = ::Eigen::Matrix<double, 2, 1>::Zero();
 
+  // TODO(austin): This feels like something that should be pulled out into
+  // a library for re-use.
+  *state = RungeKutta([this](const ::Eigen::Matrix<double, 2, 1> x) {
+    ::Eigen::Matrix<double, 3, 1> xva = FFAcceleration(x(0));
+    return (::Eigen::Matrix<double, 2, 1>() << x(1), xva(2)).finished();
+  }, *state, dt_float);
+
+  ::Eigen::Matrix<double, 3, 1> result = FFAcceleration((*state)(0));
+  (*state)(1) = result(1);
+  return result;
+}
+
+::std::vector<::Eigen::Matrix<double, 3, 1>> Trajectory::PlanXVA(
+    ::std::chrono::nanoseconds dt) {
+  ::Eigen::Matrix<double, 2, 1> state = ::Eigen::Matrix<double, 2, 1>::Zero();
   ::std::vector<::Eigen::Matrix<double, 3, 1>> result;
   result.emplace_back(FFAcceleration(0));
   result.back()(1) = 0.0;
 
-  while (state(0) < length() - 1e-4) {
-    t += dt_float;
-
-    // TODO(austin): This feels like something that should be pulled out into
-    // a library for re-use.
-    state = RungeKutta(
-        [this](const ::Eigen::Matrix<double, 2, 1> x) {
-          ::Eigen::Matrix<double, 3, 1> xva = FFAcceleration(x(0));
-          return (::Eigen::Matrix<double, 2, 1>() << x(1), xva(2)).finished();
-        },
-        state, dt_float);
-
-    result.emplace_back(FFAcceleration(state(0)));
-    state(1) = result.back()(1);
+  while (!is_at_end(state)) {
+    result.emplace_back(GetNextXVA(dt, &state));
   }
   return result;
 }
diff --git a/frc971/control_loops/drivetrain/trajectory.h b/frc971/control_loops/drivetrain/trajectory.h
index d3468b3..66dcba1 100644
--- a/frc971/control_loops/drivetrain/trajectory.h
+++ b/frc971/control_loops/drivetrain/trajectory.h
@@ -98,6 +98,11 @@
   // Returns the feed forwards voltage for an explicit distance.
   ::Eigen::Matrix<double, 2, 1> FFVoltage(double distance);
 
+  // Returns whether a state represents a state at the end of the spline.
+  bool is_at_end(::Eigen::Matrix<double, 2, 1> state) const {
+    return state(0) > length() - 1e-4;
+  }
+
   // Returns the length of the path in meters.
   double length() const { return spline_->length(); }
 
@@ -151,6 +156,10 @@
       const ::Eigen::DiagonalMatrix<double, 5> &Q,
       const ::Eigen::DiagonalMatrix<double, 2> &R) const;
 
+  // Return the next position, velocity, acceleration based on the current
+  // state. Updates the passed in state for the next iteration.
+  ::Eigen::Matrix<double, 3, 1> GetNextXVA(
+      ::std::chrono::nanoseconds dt, ::Eigen::Matrix<double, 2, 1> *state);
   ::std::vector<::Eigen::Matrix<double, 3, 1>> PlanXVA(
       ::std::chrono::nanoseconds dt);
 
diff --git a/frc971/control_loops/drivetrain/trajectory_test.cc b/frc971/control_loops/drivetrain/trajectory_test.cc
index eb1664a..f65adf1 100644
--- a/frc971/control_loops/drivetrain/trajectory_test.cc
+++ b/frc971/control_loops/drivetrain/trajectory_test.cc
@@ -265,6 +265,15 @@
             1.2e-2);
 }
 
+// Tests that Iteratively computing the XVA plan is the same as precomputing it.
+TEST_P(ParameterizedSplineTest, IterativeXVA) {
+  ::Eigen::Matrix<double, 2, 1> state = ::Eigen::Matrix<double, 2, 1>::Zero();
+  for (size_t i = 1; i < length_plan_xva_.size(); ++i) {
+    ::Eigen::Matrix<double, 3, 1> xva = trajectory_->GetNextXVA(kDt, &state);
+    EXPECT_LT((length_plan_xva_[i] - xva).norm(), 1e-2);
+  }
+}
+
 SplineTestParams MakeSplineTestParams(struct SplineTestParams params) {
   return params;
 }
diff --git a/frc971/control_loops/hybrid_state_feedback_loop_test.cc b/frc971/control_loops/hybrid_state_feedback_loop_test.cc
index 42433e9..38dbd53 100644
--- a/frc971/control_loops/hybrid_state_feedback_loop_test.cc
+++ b/frc971/control_loops/hybrid_state_feedback_loop_test.cc
@@ -150,7 +150,9 @@
   ::std::vector<::std::unique_ptr<StateFeedbackObserverCoefficients<2, 4, 7>>>
       v_observer;
   v_observer.emplace_back(new StateFeedbackObserverCoefficients<2, 4, 7>(
-      Eigen::Matrix<double, 2, 7>::Identity()));
+      Eigen::Matrix<double, 2, 7>::Identity(),
+      Eigen::Matrix<double, 2, 2>::Identity(),
+      Eigen::Matrix<double, 7, 7>::Identity()));
   StateFeedbackObserver<2, 4, 7> observer(&v_observer);
 
   StateFeedbackLoop<2, 4, 7> test_loop(
diff --git a/frc971/control_loops/profiled_subsystem.q b/frc971/control_loops/profiled_subsystem.q
index d1356da..784b92f 100644
--- a/frc971/control_loops/profiled_subsystem.q
+++ b/frc971/control_loops/profiled_subsystem.q
@@ -153,3 +153,8 @@
   // State of the estimator.
   .frc971.IndexEstimatorState estimator_state;
 };
+
+struct StaticZeroingSingleDOFProfiledSubsystemGoal {
+  double unsafe_goal;
+  .frc971.ProfileParameters profile_params;
+};
\ No newline at end of file
diff --git a/frc971/control_loops/python/BUILD b/frc971/control_loops/python/BUILD
index a0ee825..b3aa2c0 100644
--- a/frc971/control_loops/python/BUILD
+++ b/frc971/control_loops/python/BUILD
@@ -97,7 +97,7 @@
     deps = [
         ":libspline",
         ":python_init",
-    ]
+    ],
 )
 
 py_library(
@@ -166,15 +166,15 @@
 py_binary(
     name = "path_edit",
     srcs = [
-        "path_edit.py",
         "basic_window.py",
         "color.py",
+        "path_edit.py",
     ],
-    visibility = ["//visibility:public"],
     restricted_to = ["//tools:k8"],
+    visibility = ["//visibility:public"],
     deps = [
-        ":python_init",
         ":libspline",
+        ":python_init",
         "@python_gtk",
     ],
 )
@@ -183,10 +183,10 @@
     name = "basic_window",
     srcs = [
         "basic_window.py",
-        "color.py"
+        "color.py",
     ],
-    visibility = ["//visibility:public"],
     restricted_to = ["//tools:k8"],
+    visibility = ["//visibility:public"],
     deps = [
         ":python_init",
         "@python_gtk",
@@ -198,9 +198,25 @@
     srcs = [
         "color.py",
     ],
-    visibility = ["//visibility:public"],
     restricted_to = ["//tools:k8"],
+    visibility = ["//visibility:public"],
     deps = [
         ":python_init",
     ],
 )
+
+py_binary(
+    name = "static_zeroing_single_dof_profiled_subsystem_test",
+    srcs = [
+        "static_zeroing_single_dof_profiled_subsystem_test.py",
+    ],
+    legacy_create_init = False,
+    restricted_to = ["//tools:k8"],
+    deps = [
+        ":controls",
+        ":linear_system",
+        ":python_init",
+        "//external:python-gflags",
+        "//external:python-glog",
+    ],
+)
diff --git a/frc971/control_loops/python/control_loop.py b/frc971/control_loops/python/control_loop.py
index 9aa00df..e3e00b7 100644
--- a/frc971/control_loops/python/control_loop.py
+++ b/frc971/control_loops/python/control_loop.py
@@ -453,10 +453,17 @@
     if observer_coefficient_type.startswith('StateFeedbackObserver'):
       if hasattr(self, 'KalmanGain'):
         KalmanGain = self.KalmanGain
+        Q = self.Q
+        R = self.R
       else:
         KalmanGain =  numpy.linalg.inv(self.A) * self.L
+        Q = numpy.zeros(self.A.shape)
+        R = numpy.zeros((self.C.shape[0], self.C.shape[0]))
       ans.append(self._DumpMatrix('KalmanGain', KalmanGain, scalar_type))
-      ans.append('  return %s(KalmanGain);\n' % (observer_coefficient_type,))
+      ans.append(self._DumpMatrix('Q', Q, scalar_type))
+      ans.append(self._DumpMatrix('R', R, scalar_type))
+      ans.append('  return %s(KalmanGain, Q, R);\n'
+          % (observer_coefficient_type,))
 
     elif observer_coefficient_type.startswith('HybridKalman'):
       ans.append(self._DumpMatrix('Q_continuous', self.Q_continuous, scalar_type))
diff --git a/frc971/control_loops/python/drivetrain.py b/frc971/control_loops/python/drivetrain.py
index 3f9123f..c59cbab 100644
--- a/frc971/control_loops/python/drivetrain.py
+++ b/frc971/control_loops/python/drivetrain.py
@@ -362,10 +362,15 @@
         self.KalmanGain, self.Q_steady = controls.kalman(
             A=self.A, B=self.B, C=self.C, Q=self.Q, R=self.R)
 
+        # If we don't have an IMU, pad various matrices with zeros so that
+        # we can still have 4 measurement outputs.
         if not self.has_imu:
             self.KalmanGain = numpy.hstack((self.KalmanGain, numpy.matrix(numpy.zeros((7, 1)))))
             self.C = numpy.vstack((self.C, numpy.matrix(numpy.zeros((1, 7)))))
             self.D = numpy.vstack((self.D, numpy.matrix(numpy.zeros((1, 2)))))
+            Rtmp = numpy.zeros((4, 4))
+            Rtmp[0:3, 0:3] = self.R
+            self.R = Rtmp
 
         self.L = self.A * self.KalmanGain
 
diff --git a/frc971/control_loops/python/path_edit.py b/frc971/control_loops/python/path_edit.py
index 52bd8d1..9748a41 100644
--- a/frc971/control_loops/python/path_edit.py
+++ b/frc971/control_loops/python/path_edit.py
@@ -17,16 +17,16 @@
 
 from basic_window import OverrideMatrix, identity, quit_main_loop, set_color
 
-LENGTH_OF_FIELD = 323.65
+WIDTH_OF_FIELD_IN_METERS = 8.258302
 PIXELS_ON_SCREEN = 300
 
 
-def pxToIn(p):
-    return p * LENGTH_OF_FIELD / PIXELS_ON_SCREEN
+def pxToM(p):
+    return p * WIDTH_OF_FIELD_IN_METERS / PIXELS_ON_SCREEN
 
 
-def inToPx(i):
-    return (i * PIXELS_ON_SCREEN / LENGTH_OF_FIELD)
+def mToPx(i):
+    return (i * PIXELS_ON_SCREEN / WIDTH_OF_FIELD_IN_METERS)
 
 
 def px(cr):
@@ -155,7 +155,7 @@
     #John also wrote this
     def add_point(self, x, y):
         if (len(self.selected_points) < 6):
-            self.selected_points.append([x, y])
+            self.selected_points.append([pxToM(x), pxToM(y)])
             if (len(self.selected_points) == 6):
                 self.mode = Mode.kEditing
                 self.splines.append(np.array(self.selected_points))
@@ -188,9 +188,10 @@
         cur_p = [self.x, self.y]
 
         for index_splines, points in enumerate(self.spline):
-            for index_points, i in enumerate(points.curve):
+            for index_points, point in enumerate(points.curve):
                 # pythagorean
-                distance = np.sqrt((cur_p[0] - i[0])**2 + (cur_p[1] - i[1])**2)
+                distance = np.sqrt((cur_p[0] - mToPx(point[0]))**2 +
+                                   (cur_p[1] - mToPx(point[1])**2))
                 if distance < nearest:
                     nearest = distance
                     print("DISTANCE: ", distance, " | INDEX: ", index_points)
@@ -222,7 +223,7 @@
             if index > 0 and index <= self.index_of_edit:
                 distance += np.sqrt((points[index - 1][0] - point[0])**2 +
                                     (points[index - 1][1] - point[1])**2)
-        return pxToIn(distance)
+        return distance
 
     # Handle the expose-event by updating the Window and drawing
     def handle_draw(self, cr):
@@ -255,23 +256,6 @@
         cr.rectangle(-450, -150, 300, 300)
         cr.set_line_join(cairo.LINE_JOIN_ROUND)
         cr.stroke()
-        cr.rectangle((inToPx(140 - 161.825) - 300), inToPx(76.575), inToPx(56),
-                     inToPx(-153.15))
-        cr.set_line_join(cairo.LINE_JOIN_ROUND)
-        cr.stroke()
-        cr.rectangle((inToPx(161.825 - 24) - 300), inToPx(90), inToPx(24),
-                     inToPx(-180))
-        cr.set_line_join(cairo.LINE_JOIN_ROUND)
-        cr.stroke()
-
-        set_color(cr, Color(0.2, 0.2, 0.2))
-        cr.rectangle(
-            inToPx(140 - 161.825) - 300, inToPx(76.575), inToPx(56),
-            inToPx(-153.15))
-        cr.fill()
-        cr.rectangle(
-            inToPx(161.825 - 24) - 300, inToPx(90), inToPx(24), inToPx(-180))
-        cr.fill()
 
         y = 0
 
@@ -307,8 +291,8 @@
                     print(str(item))
                 for i, point in enumerate(self.selected_points):
                     print("I: " + str(i))
-                    draw_px_x(cr, point[0], point[1], 10)
-                    cr.move_to(point[0], point[1] - 15)
+                    draw_px_x(cr, mToPx(point[0]), mToPx(point[1]), 10)
+                    cr.move_to(mToPx(point[0]), mToPx(point[1]) - 15)
                     display_text(cr, str(i), 0.5, 0.5, 2, 2)
 
         elif self.mode == Mode.kEditing:
@@ -316,17 +300,14 @@
             cr.move_to(-300, 170)
             display_text(cr, "EDITING", 1, 1, 1, 1)
             if len(self.splines) > 0:
-                # print("Splines: " + str(len(self.splines)))
-                # print("ITEMS:")
                 holder_spline = []
                 for i, points in enumerate(self.splines):
                     array = np.zeros(shape=(6, 2), dtype=float)
                     for j, point in enumerate(points):
-                        array[j, 0] = point[0]
-                        array[j, 1] = point[1]
+                        array[j, 0] = mToPx(point[0])
+                        array[j, 1] = mToPx(point[1])
                     spline = Spline(np.ascontiguousarray(np.transpose(array)))
                     for k in np.linspace(0.01, 1, 100):
-
                         cr.move_to(
                             spline.Point(k - 0.01)[0],
                             spline.Point(k - 0.01)[1])
@@ -336,7 +317,6 @@
                             spline.Point(k - 0.01)[0],
                             spline.Point(k - 0.01)[1]
                         ]
-
                         holder_spline.append(holding)
                 self.curves.append(holder_spline)
 
@@ -346,13 +326,13 @@
                     for i, point in enumerate(points):
                         # print("I: " + str(i))
                         if spline == self.spline_edit and i == self.index_of_edit:
-                            draw_px_x(cr, point[0], point[1], 15,
+                            draw_px_x(cr, mToPx(point[0]), mToPx(point[1]), 15,
                                       self.colors[spline])
                         elif (spline == 0 and not i == 5) or (not i == 0
                                                               and not i == 5):
-                            draw_px_x(cr, point[0], point[1], 10,
+                            draw_px_x(cr, mToPx(point[0]), mToPx(point[1]), 10,
                                       self.colors[spline])
-                        cr.move_to(point[0], point[1] - 15)
+                        cr.move_to(mToPx(point[0]), mToPx(point[1]) - 15)
                         display_text(cr, str(i), 0.5, 0.5, 2, 2)
 
         elif self.mode == Mode.kExporting:
@@ -466,7 +446,7 @@
             if self.index_of_edit > -1 and self.held_x != self.x:
                 print("INDEX OF EDIT: " + str(self.index_of_edit))
                 self.splines[self.spline_edit][self.index_of_edit] = [
-                    self.x, self.y
+                    pxToM(self.x), pxToM(self.y)
                 ]
 
                 if not self.spline_edit == len(self.splines) - 1:
@@ -494,11 +474,11 @@
                 # Get clicked point
                 # Find nearest
                 # Move nearest to clicked
-                cur_p = [self.x, self.y]
+                cur_p = [pxToM(self.x), pxToM(self.y)]
                 print("CUR_P: " + str(self.x) + " " + str(self.y))
                 # Get the distance between each for x and y
                 # Save the index of the point closest
-                nearest = 50
+                nearest = 1  # Max distance away a the selected point can be in meters
                 index_of_closest = 0
                 for index_splines, points in enumerate(self.splines):
                     for index_points, val in enumerate(points):
@@ -520,7 +500,7 @@
 
     def do_button_press(self, event):
         print("button press activated")
-        #Be consistent with the scaling in the drawing_area
+        # Be consistent with the scaling in the drawing_area
         self.x = event.x * 2
         self.y = event.y * 2
         self.button_press_action()
@@ -622,4 +602,4 @@
 
 
 window = GridWindow()
-basic_window.RunApp()
\ No newline at end of file
+basic_window.RunApp()
diff --git a/frc971/control_loops/python/static_zeroing_single_dof_profiled_subsystem_test.py b/frc971/control_loops/python/static_zeroing_single_dof_profiled_subsystem_test.py
new file mode 100644
index 0000000..caa3082
--- /dev/null
+++ b/frc971/control_loops/python/static_zeroing_single_dof_profiled_subsystem_test.py
@@ -0,0 +1,56 @@
+#!/usr/bin/python
+
+# Generates profiled subsystem for use in
+# static_zeroing_single_dof_profiled_subsystem_test
+
+from frc971.control_loops.python import control_loop
+from frc971.control_loops.python import linear_system
+import numpy
+import sys
+import gflags
+import glog
+
+FLAGS = gflags.FLAGS
+
+try:
+    gflags.DEFINE_bool('plot', False, 'If true, plot the loop response.')
+except gflags.DuplicateFlagError:
+    pass
+
+kIntake = linear_system.LinearSystemParams(
+    name='TestIntakeSystem',
+    motor=control_loop.Vex775Pro(),
+    # (1 / 35.0) * (20.0 / 40.0) -> 16 tooth sprocket on #25 chain
+    G=(1.0 / 35.0) * (20.0 / 40.0),
+    radius=16.0 * 0.25 / (2.0 * numpy.pi) * 0.0254,
+    mass=5.4,
+    q_pos=0.015,
+    q_vel=0.3,
+    kalman_q_pos=0.12,
+    kalman_q_vel=2.00,
+    kalman_q_voltage=40.0,
+    kalman_r_position=0.05)
+
+
+def main(argv):
+    if FLAGS.plot:
+        R = numpy.matrix([[0.1], [0.0]])
+        linear_system.PlotMotion(kIntake, R)
+
+    # Write the generated constants out to a file.
+    if len(argv) != 5:
+        glog.fatal(
+            'Expected .h file name and .cc file name for the \
+            static_zeroing_single_dof_profiled_subsystem_test and integral \
+            static_zeroing_single_dof_profiled_subsystem_test.'
+        )
+    else:
+        namespaces = ['frc971', 'control_loops']
+        linear_system.WriteLinearSystem(kIntake, argv[1:3], argv[3:5],
+                                        namespaces)
+
+
+if __name__ == '__main__':
+    argv = FLAGS(sys.argv)
+    glog.init()
+    sys.exit(main(argv))
diff --git a/frc971/control_loops/state_feedback_loop.h b/frc971/control_loops/state_feedback_loop.h
index 2511d98..fc3ff34 100644
--- a/frc971/control_loops/state_feedback_loop.h
+++ b/frc971/control_loops/state_feedback_loop.h
@@ -275,10 +275,15 @@
   EIGEN_MAKE_ALIGNED_OPERATOR_NEW;
 
   const Eigen::Matrix<Scalar, number_of_states, number_of_outputs> KalmanGain;
+  const Eigen::Matrix<Scalar, number_of_states, number_of_states> Q;
+  const Eigen::Matrix<Scalar, number_of_outputs, number_of_outputs> R;
 
   StateFeedbackObserverCoefficients(
-      const Eigen::Matrix<Scalar, number_of_states, number_of_outputs> &KalmanGain)
-      : KalmanGain(KalmanGain) {}
+      const Eigen::Matrix<Scalar, number_of_states, number_of_outputs> &
+          KalmanGain,
+      const Eigen::Matrix<Scalar, number_of_states, number_of_states> &Q,
+      const Eigen::Matrix<Scalar, number_of_outputs, number_of_outputs> &R)
+      : KalmanGain(KalmanGain), Q(Q), R(R) {}
 };
 
 template <int number_of_states, int number_of_inputs, int number_of_outputs,
diff --git a/frc971/control_loops/static_zeroing_single_dof_profiled_subsystem.h b/frc971/control_loops/static_zeroing_single_dof_profiled_subsystem.h
new file mode 100644
index 0000000..9ad7439
--- /dev/null
+++ b/frc971/control_loops/static_zeroing_single_dof_profiled_subsystem.h
@@ -0,0 +1,216 @@
+#ifndef FRC971_CONTROL_LOOPS_STATIC_ZEROING_SINGLE_DOF_PROFILED_SUBSYSTEM_H_
+#define FRC971_CONTROL_LOOPS_STATIC_ZEROING_SINGLE_DOF_PROFILED_SUBSYSTEM_H_
+
+#include "frc971/control_loops/profiled_subsystem.h"
+
+namespace frc971 {
+namespace control_loops {
+
+template <typename ZeroingEstimator>
+struct StaticZeroingSingleDOFProfiledSubsystemParams {
+  // Maximum voltage while the subsystem is zeroing
+  double zeroing_voltage;
+
+  // Maximum voltage while the subsystem is running
+  double operating_voltage;
+
+  // Maximum velocity (units/s) and acceleration while State::ZEROING
+  ::frc971::ProfileParameters zeroing_profile_params;
+
+  // Maximum velocity (units/s) and acceleration while State::RUNNING if max
+  // velocity or acceleration in goal profile_params is 0
+  ::frc971::ProfileParameters default_profile_params;
+
+  // Maximum range of the subsystem in meters
+  const ::frc971::constants::Range range;
+
+  // Zeroing constants for PotAndABsoluteEncoder estimator
+  const typename ZeroingEstimator::ZeroingConstants zeroing_constants;
+
+  // Function that makes the integral loop for the subsystem
+  ::std::function<StateFeedbackLoop<3, 1, 1>()> make_integral_loop;
+};
+
+// Class for controlling and motion profiling a single degree of freedom
+// subsystem with a zeroing strategy of not moving.
+template <typename ZeroingEstimator>
+class StaticZeroingSingleDOFProfiledSubsystem {
+ public:
+  StaticZeroingSingleDOFProfiledSubsystem(
+      const StaticZeroingSingleDOFProfiledSubsystemParams<ZeroingEstimator>
+          &params);
+
+  // Returns the filtered goal of the profiled subsystem (R)
+  double goal(int row) const { return profiled_subsystem_.goal(row, 0); }
+
+  // Returns the zeroing voltage of the subsystem
+  double zeroing_voltage() { return params_.zeroing_voltage; }
+
+  // Returns the operating voltage of the subsystem
+  double operating_voltage() { return params_.operating_voltage; }
+
+  // Sets further constraints on the range constant
+  void set_min_position(double min_position) { min_position_ = min_position; }
+
+  void set_max_position(double max_position) { max_position_ = max_position; }
+
+  // Resets constrained min/max position
+  void clear_min_position() { min_position_ = params_.range.lower_hard; }
+
+  void clear_max_position() { max_position_ = params_.range.upper_hard; }
+
+  // Returns the current position
+  double position() const { return profiled_subsystem_.position(); }
+
+  void Iterate(const StaticZeroingSingleDOFProfiledSubsystemGoal *goal,
+               const typename ZeroingEstimator::Position *position,
+               double *output,
+               ::frc971::control_loops::AbsoluteProfiledJointStatus *status);
+
+  // Resets the profiled subsystem and returns to uninitialized
+  void Reset();
+
+  enum class State : int32_t {
+    UNINITIALIZED,
+    DISABLED_INITIALIZED,
+    ZEROING,
+    RUNNING,
+    ESTOP,
+  };
+
+  State state() const { return state_; }
+
+ private:
+  State state_ = State::UNINITIALIZED;
+  double min_position_, max_position_;
+
+  const StaticZeroingSingleDOFProfiledSubsystemParams<ZeroingEstimator> params_;
+
+  ::frc971::control_loops::SingleDOFProfiledSubsystem<ZeroingEstimator>
+      profiled_subsystem_;
+};
+
+template <typename ZeroingEstimator>
+StaticZeroingSingleDOFProfiledSubsystem<ZeroingEstimator>::
+    StaticZeroingSingleDOFProfiledSubsystem(
+        const StaticZeroingSingleDOFProfiledSubsystemParams<ZeroingEstimator>
+            &params)
+    : params_(params),
+      profiled_subsystem_(
+          ::std::unique_ptr<
+              ::frc971::control_loops::SimpleCappedStateFeedbackLoop<3, 1, 1>>(
+              new ::frc971::control_loops::SimpleCappedStateFeedbackLoop<
+                  3, 1, 1>(params.make_integral_loop())),
+          params.zeroing_constants, params.range,
+          params.default_profile_params.max_velocity,
+          params.default_profile_params.max_acceleration) {
+  Reset();
+};
+
+template <typename ZeroingEstimator>
+void StaticZeroingSingleDOFProfiledSubsystem<ZeroingEstimator>::Reset() {
+  state_ = State::UNINITIALIZED;
+  clear_min_position();
+  clear_max_position();
+  profiled_subsystem_.Reset();
+}
+
+template <typename ZeroingEstimator>
+void StaticZeroingSingleDOFProfiledSubsystem<ZeroingEstimator>::Iterate(
+    const StaticZeroingSingleDOFProfiledSubsystemGoal *goal,
+    const typename ZeroingEstimator::Position *position, double *output,
+    ::frc971::control_loops::AbsoluteProfiledJointStatus *status) {
+  bool disabled = output == nullptr;
+  profiled_subsystem_.Correct(*position);
+
+  switch (state_) {
+    case State::UNINITIALIZED:
+      if (profiled_subsystem_.initialized()) {
+        state_ = State::DISABLED_INITIALIZED;
+      }
+      disabled = true;
+      break;
+    case State::DISABLED_INITIALIZED:
+      // Wait here until we are either fully zeroed while disabled, or we become
+      // enabled.
+      if (disabled) {
+        if (profiled_subsystem_.zeroed()) {
+          state_ = State::RUNNING;
+        }
+      } else {
+        state_ = State::ZEROING;
+      }
+
+      // Set the goals to where we are now so when we start back up, we don't
+      // jump.
+      profiled_subsystem_.ForceGoal(profiled_subsystem_.position());
+      // Set up the profile to be the zeroing profile.
+      profiled_subsystem_.AdjustProfile(params_.zeroing_profile_params);
+
+      // We are not ready to start doing anything yet.
+      disabled = true;
+      break;
+    case State::ZEROING:
+      // Now, zero by actively holding still.
+      if (profiled_subsystem_.zeroed()) {
+        state_ = State::RUNNING;
+      } else if (disabled) {
+        state_ = State::DISABLED_INITIALIZED;
+      }
+      break;
+
+    case State::RUNNING: {
+      if (disabled) {
+        // Reset the profile to the current position so it starts from here when
+        // we get re-enabled.
+        profiled_subsystem_.ForceGoal(profiled_subsystem_.position());
+      }
+
+      if (goal) {
+        profiled_subsystem_.AdjustProfile(goal->profile_params);
+
+        double safe_goal = goal->unsafe_goal;
+        if (safe_goal < min_position_) {
+          LOG(DEBUG, "Limiting to %f from %f\n", min_position_, safe_goal);
+          safe_goal = min_position_;
+        }
+        if (safe_goal > max_position_) {
+          LOG(DEBUG, "Limiting to %f from %f\n", max_position_, safe_goal);
+          safe_goal = max_position_;
+        }
+        profiled_subsystem_.set_unprofiled_goal(safe_goal);
+      }
+    } break;
+
+    case State::ESTOP:
+      LOG(ERROR, "Estop\n");
+      disabled = true;
+      break;
+  }
+
+  // Set the voltage limits.
+  const double max_voltage = (state_ == State::RUNNING)
+                                 ? params_.operating_voltage
+                                 : params_.zeroing_voltage;
+
+  profiled_subsystem_.set_max_voltage({{max_voltage}});
+
+  // Calculate the loops for a cycle.
+  profiled_subsystem_.Update(disabled);
+
+  // Write out all the voltages.
+  if (output) {
+    *output = profiled_subsystem_.voltage();
+  }
+
+  status->zeroed = profiled_subsystem_.zeroed();
+
+  profiled_subsystem_.PopulateStatus(status);
+  status->estopped = (state_ == State::ESTOP);
+  status->state = static_cast<int32_t>(state_);
+}
+
+}  // namespace control_loops
+}  // namespace frc971
+
+#endif  // FRC971_CONTROL_LOOPS_STATIC_ZEROING_SINGLE_DOF_PROFILED_SUBSYSTEM_H_
\ No newline at end of file
diff --git a/frc971/control_loops/static_zeroing_single_dof_profiled_subsystem_test.cc b/frc971/control_loops/static_zeroing_single_dof_profiled_subsystem_test.cc
new file mode 100644
index 0000000..8805842
--- /dev/null
+++ b/frc971/control_loops/static_zeroing_single_dof_profiled_subsystem_test.cc
@@ -0,0 +1,492 @@
+#include "gtest/gtest.h"
+
+#include "aos/controls/control_loop_test.h"
+#include "frc971/control_loops/capped_test_plant.h"
+#include "frc971/control_loops/position_sensor_sim.h"
+#include "frc971/control_loops/static_zeroing_single_dof_profiled_subsystem.h"
+#include "frc971/control_loops/static_zeroing_single_dof_profiled_subsystem_test_integral_plant.h"
+#include "frc971/control_loops/static_zeroing_single_dof_profiled_subsystem_test_plant.h"
+
+using ::frc971::control_loops::PositionSensorSimulator;
+
+namespace frc971 {
+namespace control_loops {
+namespace {
+constexpr double kNoiseScalar = 0.01;
+
+namespace chrono = ::std::chrono;
+using ::aos::monotonic_clock;
+
+struct TestIntakeSystemValues {
+  static const int kZeroingSampleSize = 200;
+
+  static constexpr double kEncoderRatio =
+      (16.0 * 0.25) * (20.0 / 40.0) / (2.0 * M_PI) * 0.0254;
+  static constexpr double kEncoderIndexDifference = 2.0 * M_PI * kEncoderRatio;
+  static constexpr ::frc971::constants::Range kRange{
+      .lower_hard = -0.01, .upper_hard = 0.250, .lower = 0.01, .upper = 0.235};
+
+  static constexpr double kZeroingVoltage = 2.5;
+  static constexpr double kOperatingVoltage = 12.0;
+
+  static const ::frc971::ProfileParameters kDefaultParams;
+  static const ::frc971::ProfileParameters kZeroingParams;
+
+  static constexpr ::frc971::constants::PotAndAbsoluteEncoderZeroingConstants
+      kZeroing{kZeroingSampleSize, kEncoderIndexDifference, 0, 0.0005, 20, 1.9};
+
+  static const StaticZeroingSingleDOFProfiledSubsystemParams<
+      zeroing::PotAndAbsoluteEncoderZeroingEstimator>
+      kParams;
+};
+
+constexpr ::frc971::constants::Range TestIntakeSystemValues::kRange;
+constexpr ::frc971::constants::PotAndAbsoluteEncoderZeroingConstants
+    TestIntakeSystemValues::kZeroing;
+const ::frc971::ProfileParameters TestIntakeSystemValues::kDefaultParams{0.3,
+                                                                         5.0};
+const ::frc971::ProfileParameters TestIntakeSystemValues::kZeroingParams{0.1,
+                                                                         1.0};
+
+const StaticZeroingSingleDOFProfiledSubsystemParams<
+    zeroing::PotAndAbsoluteEncoderZeroingEstimator>
+    TestIntakeSystemValues::kParams(
+        {.zeroing_voltage = TestIntakeSystemValues::kZeroingVoltage,
+         .operating_voltage = TestIntakeSystemValues::kOperatingVoltage,
+         .zeroing_profile_params = TestIntakeSystemValues::kZeroingParams,
+         .default_profile_params = TestIntakeSystemValues::kDefaultParams,
+         .range = TestIntakeSystemValues::kRange,
+         .zeroing_constants = TestIntakeSystemValues::kZeroing,
+         .make_integral_loop = MakeIntegralTestIntakeSystemLoop});
+
+struct TestIntakeSystemData {
+  ::frc971::control_loops::StaticZeroingSingleDOFProfiledSubsystemGoal goal;
+
+  ::frc971::control_loops::AbsoluteProfiledJointStatus status;
+
+  ::frc971::PotAndAbsolutePosition position;
+
+  double output;
+};
+
+}  // namespace
+
+class TestIntakeSystemSimulation {
+ public:
+  TestIntakeSystemSimulation()
+      : subsystem_plant_(new CappedTestPlant(
+            ::frc971::control_loops::MakeTestIntakeSystemPlant())),
+        subsystem_pot_encoder_(
+            TestIntakeSystemValues::kEncoderIndexDifference) {
+    // Start the subsystem out in the middle by default.
+    InitializeSubsystemPosition((TestIntakeSystemValues::kRange.lower +
+                                 TestIntakeSystemValues::kRange.upper) /
+                                2.0);
+  }
+
+  void InitializeSubsystemPosition(double start_pos) {
+    subsystem_plant_->mutable_X(0, 0) = start_pos;
+    subsystem_plant_->mutable_X(1, 0) = 0.0;
+
+    subsystem_pot_encoder_.Initialize(
+        start_pos, kNoiseScalar, 0.0,
+        TestIntakeSystemValues::kZeroing.measured_absolute_position);
+  }
+
+  // Updates the position message with the position of the subsystem.
+  void UpdatePositionMessage(::frc971::PotAndAbsolutePosition *position) {
+    subsystem_pot_encoder_.GetSensorValues(position);
+  }
+
+  double subsystem_position() const { return subsystem_plant_->X(0, 0); }
+  double subsystem_velocity() const { return subsystem_plant_->X(1, 0); }
+
+  // Sets the difference between the commanded and applied powers.
+  // This lets us test that the integrators work.
+  void set_subsystem_voltage_offset(double voltage_offset) {
+    subsystem_plant_->set_voltage_offset(voltage_offset);
+  }
+
+  // Simulates the subsystem for a single timestep.
+  void Simulate(const double output_voltage, const int32_t state) {
+    const double voltage_check_subsystem =
+        (static_cast<StaticZeroingSingleDOFProfiledSubsystem<
+             zeroing::PotAndAbsoluteEncoderZeroingEstimator>::State>(state) ==
+         StaticZeroingSingleDOFProfiledSubsystem<
+             zeroing::PotAndAbsoluteEncoderZeroingEstimator>::State::RUNNING)
+            ? TestIntakeSystemValues::kOperatingVoltage
+            : TestIntakeSystemValues::kZeroingVoltage;
+
+    EXPECT_LE(::std::abs(output_voltage), voltage_check_subsystem);
+
+    ::Eigen::Matrix<double, 1, 1> subsystem_U;
+    subsystem_U << output_voltage + subsystem_plant_->voltage_offset();
+    subsystem_plant_->Update(subsystem_U);
+
+    const double position_subsystem = subsystem_plant_->Y(0, 0);
+
+    subsystem_pot_encoder_.MoveTo(position_subsystem);
+
+    EXPECT_GE(position_subsystem, TestIntakeSystemValues::kRange.lower_hard);
+    EXPECT_LE(position_subsystem, TestIntakeSystemValues::kRange.upper_hard);
+  }
+
+ private:
+  ::std::unique_ptr<CappedTestPlant> subsystem_plant_;
+  PositionSensorSimulator subsystem_pot_encoder_;
+};
+
+class IntakeSystemTest : public ::aos::testing::ControlLoopTest {
+ protected:
+  IntakeSystemTest()
+      : subsystem_(TestIntakeSystemValues::kParams), subsystem_plant_() {}
+
+  void VerifyNearGoal() {
+    EXPECT_NEAR(subsystem_data_.goal.unsafe_goal,
+                subsystem_data_.status.position, 0.001);
+    EXPECT_NEAR(subsystem_data_.goal.unsafe_goal,
+                subsystem_plant_.subsystem_position(), 0.001);
+    EXPECT_NEAR(subsystem_data_.status.velocity, 0, 0.001);
+  }
+
+  // Runs one iteration of the whole simulation.
+  void RunIteration(bool enabled = true, bool null_goal = false) {
+    SendMessages(enabled);
+    subsystem_plant_.UpdatePositionMessage(&subsystem_data_.position);
+
+    // Checks if the robot was reset and resets the subsystem.
+    // Required since there is no ControlLoop to reset it (ie. a superstructure)
+    ::aos::robot_state.FetchLatest();
+    if (::aos::robot_state.get() &&
+        sensor_reader_pid_ != ::aos::robot_state->reader_pid) {
+      LOG(ERROR, "WPILib reset, restarting\n");
+      subsystem_.Reset();
+    }
+
+    sensor_reader_pid_ = ::aos::robot_state->reader_pid;
+    subsystem_goal_.unsafe_goal = subsystem_data_.goal.unsafe_goal;
+    subsystem_goal_.profile_params = subsystem_data_.goal.profile_params;
+
+    subsystem_.Iterate(null_goal ? nullptr : &subsystem_goal_,
+                       &subsystem_data_.position, &subsystem_data_.output,
+                       &subsystem_data_.status);
+
+    subsystem_plant_.Simulate(subsystem_data_.output,
+                              subsystem_data_.status.state);
+
+    TickTime(::std::chrono::microseconds(5050));
+  }
+
+  // Runs iterations until the specified amount of simulated time has elapsed.
+  void RunForTime(const monotonic_clock::duration run_for, bool enabled = true,
+                  bool null_goal = false) {
+    const auto start_time = monotonic_clock::now();
+    while (monotonic_clock::now() < start_time + run_for) {
+      const auto loop_start_time = monotonic_clock::now();
+      double begin_subsystem_velocity = subsystem_plant_.subsystem_velocity();
+
+      RunIteration(enabled, null_goal);
+
+      const double loop_time = chrono::duration_cast<chrono::duration<double>>(
+                                   monotonic_clock::now() - loop_start_time)
+                                   .count();
+      const double subsystem_acceleration =
+          (subsystem_plant_.subsystem_velocity() - begin_subsystem_velocity) /
+          loop_time;
+      EXPECT_NEAR(subsystem_acceleration, 0.0, peak_subsystem_acceleration_);
+      EXPECT_NEAR(subsystem_plant_.subsystem_velocity(), 0.0,
+                  peak_subsystem_velocity_);
+    }
+  }
+
+  void set_peak_subsystem_acceleration(double value) {
+    peak_subsystem_acceleration_ = value;
+  }
+  void set_peak_subsystem_velocity(double value) {
+    peak_subsystem_velocity_ = value;
+  }
+
+  // Create a new instance of the test queue so that it invalidates the queue
+  // that it points to.  Otherwise, we will have a pointer to shared memory
+  // that is no longer valid.
+  // TestIntakeSystemData subsystem_data_;
+
+  // Create a control loop and simulation.
+  StaticZeroingSingleDOFProfiledSubsystem<
+      zeroing::PotAndAbsoluteEncoderZeroingEstimator>
+      subsystem_;
+  TestIntakeSystemSimulation subsystem_plant_;
+
+  StaticZeroingSingleDOFProfiledSubsystemGoal subsystem_goal_;
+
+  TestIntakeSystemData subsystem_data_;
+
+ private:
+  // The acceleration limits to check for while moving.
+  double peak_subsystem_acceleration_ = 1e10;
+  // The velocity limits to check for while moving.
+  double peak_subsystem_velocity_ = 1e10;
+
+  int32_t sensor_reader_pid_ = 0;
+};
+
+// Tests that the subsystem does nothing when the goal is zero.
+TEST_F(IntakeSystemTest, DoesNothing) {
+  // Intake system uses 0.05 to test for 0.
+  subsystem_data_.goal.unsafe_goal = 0.05;
+  RunForTime(chrono::seconds(5));
+
+  VerifyNearGoal();
+}
+
+// Tests that the subsystem loop can reach a goal.
+TEST_F(IntakeSystemTest, ReachesGoal) {
+  // Set a reasonable goal.
+  auto &goal = subsystem_data_.goal;
+  goal.unsafe_goal = 0.1;
+  goal.profile_params.max_velocity = 1;
+  goal.profile_params.max_acceleration = 0.5;
+
+  // Give it a lot of time to get there.
+  RunForTime(chrono::seconds(8));
+
+  VerifyNearGoal();
+}
+
+// Makes sure that the voltage on a motor is properly pulled back after
+// saturation such that we don't get weird or bad (e.g. oscillating) behaviour.
+TEST_F(IntakeSystemTest, SaturationTest) {
+  // Zero it before we move.
+  auto &goal = subsystem_data_.goal;
+  goal.unsafe_goal = TestIntakeSystemValues::kRange.upper;
+  RunForTime(chrono::seconds(8));
+  VerifyNearGoal();
+
+  // Try a low acceleration move with a high max velocity and verify the
+  // acceleration is capped like expected.
+  {
+    goal.unsafe_goal = TestIntakeSystemValues::kRange.lower;
+    goal.profile_params.max_velocity = 20.0;
+    goal.profile_params.max_acceleration = 0.1;
+  }
+  set_peak_subsystem_velocity(23.0);
+  set_peak_subsystem_acceleration(0.2);
+
+  RunForTime(chrono::seconds(8));
+  VerifyNearGoal();
+
+  // Now do a high acceleration move with a low velocity limit.
+  {
+    goal.unsafe_goal = TestIntakeSystemValues::kRange.upper;
+    goal.profile_params.max_velocity = 0.1;
+    goal.profile_params.max_acceleration = 100;
+  }
+
+  set_peak_subsystem_velocity(0.2);
+  set_peak_subsystem_acceleration(103);
+  RunForTime(chrono::seconds(8));
+
+  VerifyNearGoal();
+}
+
+// Tests that the subsystem loop doesn't try and go beyond it's physical range
+// of the mechanisms.
+TEST_F(IntakeSystemTest, RespectsRange) {
+  auto &goal = subsystem_data_.goal;
+  // Set some ridiculous goals to test upper limits.
+  {
+    goal.unsafe_goal = 100.0;
+    goal.profile_params.max_velocity = 1;
+    goal.profile_params.max_acceleration = 0.5;
+  }
+  RunForTime(chrono::seconds(10));
+
+  // Check that we are near our soft limit.
+  EXPECT_NEAR(TestIntakeSystemValues::kRange.upper,
+              subsystem_data_.status.position, 0.001);
+
+  // Set some ridiculous goals to test lower limits.
+  {
+    goal.unsafe_goal = -100.0;
+    goal.profile_params.max_velocity = 1;
+    goal.profile_params.max_acceleration = 0.5;
+  }
+
+  RunForTime(chrono::seconds(10));
+
+  // Check that we are near our soft limit.
+  EXPECT_NEAR(TestIntakeSystemValues::kRange.lower,
+              subsystem_data_.status.position, 0.001);
+}
+
+// Tests that the subsystem loop zeroes when run for a while.
+TEST_F(IntakeSystemTest, ZeroTest) {
+  auto &goal = subsystem_data_.goal;
+  {
+    goal.unsafe_goal = TestIntakeSystemValues::kRange.upper;
+    goal.profile_params.max_velocity = 1;
+    goal.profile_params.max_acceleration = 0.5;
+  }
+
+  RunForTime(chrono::seconds(10));
+
+  VerifyNearGoal();
+}
+
+// Tests that the loop zeroes when run for a while without a goal.
+TEST_F(IntakeSystemTest, ZeroNoGoal) {
+  RunForTime(chrono::seconds(5));
+
+  EXPECT_EQ(StaticZeroingSingleDOFProfiledSubsystem<
+                zeroing::PotAndAbsoluteEncoderZeroingEstimator>::State::RUNNING,
+            subsystem_.state());
+}
+
+TEST_F(IntakeSystemTest, LowerHardstopStartup) {
+  subsystem_plant_.InitializeSubsystemPosition(
+      TestIntakeSystemValues::kRange.lower_hard);
+  { subsystem_data_.goal.unsafe_goal = TestIntakeSystemValues::kRange.upper; }
+  RunForTime(chrono::seconds(10));
+
+  VerifyNearGoal();
+}
+
+// Tests that starting at the upper hardstops doesn't cause an abort.
+TEST_F(IntakeSystemTest, UpperHardstopStartup) {
+  subsystem_plant_.InitializeSubsystemPosition(
+      TestIntakeSystemValues::kRange.upper_hard);
+  { subsystem_data_.goal.unsafe_goal = TestIntakeSystemValues::kRange.upper; }
+  RunForTime(chrono::seconds(10));
+
+  VerifyNearGoal();
+}
+
+// Tests that resetting WPILib results in a rezero.
+TEST_F(IntakeSystemTest, ResetTest) {
+  subsystem_plant_.InitializeSubsystemPosition(
+      TestIntakeSystemValues::kRange.upper);
+  {
+    subsystem_data_.goal.unsafe_goal =
+        TestIntakeSystemValues::kRange.upper - 0.1;
+  }
+  RunForTime(chrono::seconds(10));
+
+  EXPECT_EQ(StaticZeroingSingleDOFProfiledSubsystem<
+                zeroing::PotAndAbsoluteEncoderZeroingEstimator>::State::RUNNING,
+            subsystem_.state());
+
+  VerifyNearGoal();
+  SimulateSensorReset();
+  RunForTime(chrono::milliseconds(100));
+
+  EXPECT_EQ(
+      StaticZeroingSingleDOFProfiledSubsystem<
+          zeroing::PotAndAbsoluteEncoderZeroingEstimator>::State::UNINITIALIZED,
+      subsystem_.state());
+
+  RunForTime(chrono::seconds(10));
+
+  EXPECT_EQ(StaticZeroingSingleDOFProfiledSubsystem<
+                zeroing::PotAndAbsoluteEncoderZeroingEstimator>::State::RUNNING,
+            subsystem_.state());
+  VerifyNearGoal();
+}
+
+// Tests that the internal goals don't change while disabled.
+TEST_F(IntakeSystemTest, DisabledGoalTest) {
+  {
+    subsystem_data_.goal.unsafe_goal =
+        TestIntakeSystemValues::kRange.lower + 0.03;
+  }
+
+  // Checks that the subsystem has not moved from its starting position at 0
+  RunForTime(chrono::milliseconds(100), false);
+  EXPECT_EQ(0.0, subsystem_.goal(0));
+
+  // Now make sure they move correctly
+  RunForTime(chrono::seconds(4), true);
+  EXPECT_NE(0.0, subsystem_.goal(0));
+}
+
+// Tests that zeroing while disabled works.
+TEST_F(IntakeSystemTest, DisabledZeroTest) {
+  { subsystem_data_.goal.unsafe_goal = TestIntakeSystemValues::kRange.lower; }
+
+  // Run disabled for 2 seconds
+  RunForTime(chrono::seconds(2), false);
+  EXPECT_EQ(StaticZeroingSingleDOFProfiledSubsystem<
+                zeroing::PotAndAbsoluteEncoderZeroingEstimator>::State::RUNNING,
+            subsystem_.state());
+
+  RunForTime(chrono::seconds(4), true);
+
+  VerifyNearGoal();
+}
+
+// Tests that set_min_position limits range properly
+TEST_F(IntakeSystemTest, MinPositionTest) {
+  subsystem_data_.goal.unsafe_goal = TestIntakeSystemValues::kRange.lower_hard;
+  RunForTime(chrono::seconds(2), true);
+
+  // Check that kRange.lower is used as the default min position
+  EXPECT_EQ(subsystem_.goal(0), TestIntakeSystemValues::kRange.lower);
+  EXPECT_NEAR(subsystem_data_.status.position,
+              TestIntakeSystemValues::kRange.lower, 0.001);
+
+  // Set min position and check that the subsystem increases to that position
+  subsystem_.set_min_position(TestIntakeSystemValues::kRange.lower + 0.05);
+  RunForTime(chrono::seconds(2), true);
+  EXPECT_EQ(subsystem_.goal(0), TestIntakeSystemValues::kRange.lower + 0.05);
+  EXPECT_NEAR(subsystem_data_.status.position,
+              TestIntakeSystemValues::kRange.lower + 0.05, 0.001);
+
+  // Clear min position and check that the subsystem returns to kRange.lower
+  subsystem_.clear_min_position();
+  RunForTime(chrono::seconds(2), true);
+  EXPECT_EQ(subsystem_.goal(0), TestIntakeSystemValues::kRange.lower);
+  EXPECT_NEAR(subsystem_data_.status.position,
+              TestIntakeSystemValues::kRange.lower, 0.001);
+}
+
+// Tests that set_max_position limits range properly
+TEST_F(IntakeSystemTest, MaxPositionTest) {
+  subsystem_data_.goal.unsafe_goal = TestIntakeSystemValues::kRange.upper_hard;
+  RunForTime(chrono::seconds(2), true);
+
+  // Check that kRange.upper is used as the default max position
+  EXPECT_EQ(subsystem_.goal(0), TestIntakeSystemValues::kRange.upper);
+  EXPECT_NEAR(subsystem_data_.status.position,
+              TestIntakeSystemValues::kRange.upper, 0.001);
+
+  // Set max position and check that the subsystem lowers to that position
+  subsystem_.set_max_position(TestIntakeSystemValues::kRange.upper - 0.05);
+  RunForTime(chrono::seconds(2), true);
+  EXPECT_EQ(subsystem_.goal(0), TestIntakeSystemValues::kRange.upper - 0.05);
+  EXPECT_NEAR(subsystem_data_.status.position,
+              TestIntakeSystemValues::kRange.upper - 0.05, 0.001);
+
+  // Clear max position and check that the subsystem returns to kRange.upper
+  subsystem_.clear_max_position();
+  RunForTime(chrono::seconds(2), true);
+  EXPECT_EQ(subsystem_.goal(0), TestIntakeSystemValues::kRange.upper);
+  EXPECT_NEAR(subsystem_data_.status.position,
+              TestIntakeSystemValues::kRange.upper, 0.001);
+}
+
+// Tests that the subsystem maintains its current position when sent a null goal
+TEST_F(IntakeSystemTest, NullGoalTest) {
+  subsystem_data_.goal.unsafe_goal =
+      TestIntakeSystemValues::kRange.lower + 0.05;
+  RunForTime(chrono::seconds(2), true);
+
+  VerifyNearGoal();
+
+  // Run with a null goal
+  RunForTime(chrono::seconds(2), true, true);
+
+  // Check that the subsystem has not moved
+  VerifyNearGoal();
+}
+
+}  // namespace control_loops
+}  // namespace frc971
diff --git a/frc971/wpilib/sensor_reader.h b/frc971/wpilib/sensor_reader.h
index c843735..be96eea 100644
--- a/frc971/wpilib/sensor_reader.h
+++ b/frc971/wpilib/sensor_reader.h
@@ -141,6 +141,27 @@
         encoder_ratio * (2.0 * M_PI);
   }
 
+  void CopyPosition(
+      const ::frc971::wpilib::DMAEncoderAndPotentiometer &encoder,
+      ::frc971::PotAndIndexPosition *position,
+      ::std::function<double(int32_t)> encoder_translate,
+      ::std::function<double(double)> potentiometer_translate, bool reverse,
+      double pot_offset) {
+    const double multiplier = reverse ? -1.0 : 1.0;
+    position->encoder =
+        multiplier * encoder_translate(encoder.polled_encoder_value());
+    position->pot = multiplier * potentiometer_translate(
+                                     encoder.polled_potentiometer_voltage()) +
+                    pot_offset;
+    position->latched_encoder =
+        multiplier * encoder_translate(encoder.last_encoder_value());
+    position->latched_pot =
+        multiplier *
+            potentiometer_translate(encoder.last_potentiometer_voltage()) +
+        pot_offset;
+    position->index_pulses = encoder.index_posedge_count();
+  }
+
   double encoder_translate(int32_t value, double counts_per_revolution,
                            double ratio) {
     return static_cast<double>(value) / counts_per_revolution * ratio *
diff --git a/third_party/pycrc/BUILD b/third_party/pycrc/BUILD
new file mode 100644
index 0000000..50a21e1
--- /dev/null
+++ b/third_party/pycrc/BUILD
@@ -0,0 +1,25 @@
+licenses(["notice"])
+
+genrule(
+    name = "copy_main",
+    srcs = [
+        "pycrc.py",
+    ],
+    outs = [
+        "pycrc_main.py",
+    ],
+    cmd = "cp $< $@",
+)
+
+py_binary(
+    name = "pycrc_main",
+    srcs = glob([
+        "pycrc/*.py",
+    ]) + [
+        "pycrc_main.py",
+    ],
+    imports = ["."],
+    legacy_create_init = False,
+    main = "pycrc_main.py",
+    visibility = ["//visibility:public"],
+)
diff --git a/y2016/wpilib_interface.cc b/y2016/wpilib_interface.cc
index ee4b897..787d9a5 100644
--- a/y2016/wpilib_interface.cc
+++ b/y2016/wpilib_interface.cc
@@ -1,13 +1,13 @@
+#include <inttypes.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
-#include <inttypes.h>
 
-#include <chrono>
-#include <thread>
-#include <mutex>
-#include <functional>
 #include <array>
+#include <chrono>
+#include <functional>
+#include <mutex>
+#include <thread>
 
 #include "frc971/wpilib/ahal/AnalogInput.h"
 #include "frc971/wpilib/ahal/Compressor.h"
@@ -234,7 +234,6 @@
     autonomous_modes_.at(i) = ::std::move(sensor);
   }
 
-
   // All of the DMA-related set_* calls must be made before this, and it doesn't
   // hurt to do all of them.
 
@@ -278,16 +277,15 @@
 
     {
       auto superstructure_message = superstructure_queue.position.MakeMessage();
-      CopyPotAndIndexPosition(intake_encoder_, &superstructure_message->intake,
-                              intake_translate, intake_pot_translate, false,
-                              values.intake.pot_offset);
-      CopyPotAndIndexPosition(shoulder_encoder_,
-                              &superstructure_message->shoulder,
-                              shoulder_translate, shoulder_pot_translate, false,
-                              values.shoulder.pot_offset);
-      CopyPotAndIndexPosition(wrist_encoder_, &superstructure_message->wrist,
-                              wrist_translate, wrist_pot_translate, true,
-                              values.wrist.pot_offset);
+      CopyPosition(intake_encoder_, &superstructure_message->intake,
+                   intake_translate, intake_pot_translate, false,
+                   values.intake.pot_offset);
+      CopyPosition(shoulder_encoder_, &superstructure_message->shoulder,
+                   shoulder_translate, shoulder_pot_translate, false,
+                   values.shoulder.pot_offset);
+      CopyPosition(wrist_encoder_, &superstructure_message->wrist,
+                   wrist_translate, wrist_pot_translate, true,
+                   values.wrist.pot_offset);
 
       superstructure_message.Send();
     }
@@ -314,27 +312,6 @@
   }
 
  private:
-  void CopyPotAndIndexPosition(
-      const ::frc971::wpilib::DMAEncoderAndPotentiometer &encoder,
-      ::frc971::PotAndIndexPosition *position,
-      ::std::function<double(int32_t)> encoder_translate,
-      ::std::function<double(double)> potentiometer_translate, bool reverse,
-      double pot_offset) {
-    const double multiplier = reverse ? -1.0 : 1.0;
-    position->encoder =
-        multiplier * encoder_translate(encoder.polled_encoder_value());
-    position->pot = multiplier * potentiometer_translate(
-                                     encoder.polled_potentiometer_voltage()) +
-                    pot_offset;
-    position->latched_encoder =
-        multiplier * encoder_translate(encoder.last_encoder_value());
-    position->latched_pot =
-        multiplier *
-            potentiometer_translate(encoder.last_potentiometer_voltage()) +
-        pot_offset;
-    position->index_pulses = encoder.index_posedge_count();
-  }
-
   ::std::unique_ptr<AnalogInput> drivetrain_left_hall_, drivetrain_right_hall_;
 
   ::std::unique_ptr<Encoder> shooter_left_encoder_, shooter_right_encoder_;
@@ -353,9 +330,7 @@
       : pcm_(pcm),
         drivetrain_(".frc971.control_loops.drivetrain_queue.output"),
         shooter_(".y2016.control_loops.shooter.shooter_queue.output"),
-        superstructure_(
-            ".y2016.control_loops.superstructure_queue.output") {
-  }
+        superstructure_(".y2016.control_loops.superstructure_queue.output") {}
 
   void set_compressor(::std::unique_ptr<Compressor> compressor) {
     compressor_ = ::std::move(compressor);
@@ -371,8 +346,7 @@
     climber_trigger_ = ::std::move(s);
   }
 
-  void set_traverse(
-      ::std::unique_ptr<::frc971::wpilib::BufferedSolenoid> s) {
+  void set_traverse(::std::unique_ptr<::frc971::wpilib::BufferedSolenoid> s) {
     traverse_ = ::std::move(s);
   }
 
@@ -391,8 +365,7 @@
     shooter_pusher_ = ::std::move(s);
   }
 
-  void set_lights(
-      ::std::unique_ptr<::frc971::wpilib::BufferedSolenoid> s) {
+  void set_lights(::std::unique_ptr<::frc971::wpilib::BufferedSolenoid> s) {
     lights_ = ::std::move(s);
   }
 
@@ -462,9 +435,7 @@
 
       {
         ::frc971::wpilib::PneumaticsToLog to_log;
-        {
-          to_log.compressor_on = compressor_->Enabled();
-        }
+        { to_log.compressor_on = compressor_->Enabled(); }
 
         pcm_->Flush();
         to_log.read_solenoids = pcm_->GetAll();
@@ -486,8 +457,7 @@
 
   ::aos::Queue<::frc971::control_loops::DrivetrainQueue::Output> drivetrain_;
   ::aos::Queue<::y2016::control_loops::shooter::ShooterQueue::Output> shooter_;
-  ::aos::Queue<
-      ::y2016::control_loops::SuperstructureQueue::Output>
+  ::aos::Queue<::y2016::control_loops::SuperstructureQueue::Output>
       superstructure_;
 
   ::std::atomic<bool> run_{true};
diff --git a/y2019/BUILD b/y2019/BUILD
index ad35ead..2eb5e24 100644
--- a/y2019/BUILD
+++ b/y2019/BUILD
@@ -1,3 +1,13 @@
+load("//frc971:downloader.bzl", "robot_downloader")
+
+robot_downloader(
+    start_binaries = [
+        ":joystick_reader",
+        ":wpilib_interface",
+        "//y2019/control_loops/drivetrain:drivetrain",
+    ],
+)
+
 cc_library(
     name = "constants",
     srcs = [
@@ -55,7 +65,8 @@
         "//third_party/Phoenix-frc-lib:phoenix",
     ],
 )
-cc_library(
+
+cc_binary(
     name = "joystick_reader",
     srcs = [
         ":joystick_reader.cc",
@@ -63,9 +74,9 @@
     deps = [
         "//aos:init",
         "//aos/actions:action_lib",
+        "//aos/input:action_joystick_input",
         "//aos/input:drivetrain_input",
         "//aos/input:joystick_input",
-        "//aos/input:action_joystick_input",
         "//aos/logging",
         "//aos/network:team_number",
         "//aos/stl_mutex",
diff --git a/y2019/constants.h b/y2019/constants.h
index e7c178b..e68143c 100644
--- a/y2019/constants.h
+++ b/y2019/constants.h
@@ -1,8 +1,8 @@
 #ifndef Y2019_CONSTANTS_H_
 #define Y2019_CONSTANTS_H_
 
-#include <stdint.h>
 #include <math.h>
+#include <stdint.h>
 
 #include "frc971/constants.h"
 #include "y2019/control_loops/drivetrain/drivetrain_dog_motor_plant.h"
@@ -28,7 +28,7 @@
     return kDrivetrainCyclesPerRevolution() * 4;
   }
   static constexpr double kDrivetrainEncoderRatio() {
-    return (52.0 / 24.0);
+    return (24.0 / 52.0);
   }
   static constexpr double kMaxDrivetrainEncoderPulsesPerSecond() {
     return control_loops::drivetrain::kFreeSpeed / (2.0 * M_PI) *
diff --git a/y2019/control_loops/python/BUILD b/y2019/control_loops/python/BUILD
index f3e4ca1..b038507 100644
--- a/y2019/control_loops/python/BUILD
+++ b/y2019/control_loops/python/BUILD
@@ -105,9 +105,9 @@
 )
 
 py_binary(
-    name = "lift",
+    name = "stilts",
     srcs = [
-        "lift.py",
+        "stilts.py",
     ],
     legacy_create_init = False,
     restricted_to = ["//tools:k8"],
diff --git a/y2019/control_loops/python/lift.py b/y2019/control_loops/python/stilts.py
similarity index 82%
rename from y2019/control_loops/python/lift.py
rename to y2019/control_loops/python/stilts.py
index dab2754..8faa5d4 100755
--- a/y2019/control_loops/python/lift.py
+++ b/y2019/control_loops/python/stilts.py
@@ -14,8 +14,8 @@
 except gflags.DuplicateFlagError:
     pass
 
-kLift = linear_system.LinearSystemParams(
-    name='Lift',
+kStilts = linear_system.LinearSystemParams(
+    name='Stilts',
     motor=control_loop.Vex775Pro(),
     G=(12.0 / 100.0) * (14.0 / 52.0),
     # 5mm pitch, 18 tooth
@@ -34,8 +34,8 @@
 def main(argv):
     if FLAGS.plot:
         R = numpy.matrix([[1.5], [0.0]])
-        linear_system.PlotKick(kLift, R)
-        linear_system.PlotMotion(kLift, R, max_velocity=5.0)
+        linear_system.PlotKick(kStilts, R)
+        linear_system.PlotMotion(kStilts, R, max_velocity=5.0)
 
     # Write the generated constants out to a file.
     if len(argv) != 5:
@@ -43,8 +43,8 @@
             'Expected .h file name and .cc file name for the elevator and integral elevator.'
         )
     else:
-        namespaces = ['y2019', 'control_loops', 'superstructure', 'lift']
-        linear_system.WriteLinearSystem(kLift, argv[1:3], argv[3:5],
+        namespaces = ['y2019', 'control_loops', 'superstructure', 'stilts']
+        linear_system.WriteLinearSystem(kStilts, argv[1:3], argv[3:5],
                                         namespaces)
 
 
diff --git a/y2019/jevois/BUILD b/y2019/jevois/BUILD
index 8a8bca3..871ee15 100644
--- a/y2019/jevois/BUILD
+++ b/y2019/jevois/BUILD
@@ -1,3 +1,57 @@
+spi_crc_args = [
+    "$(location //third_party/pycrc:pycrc_main)",
+    "--width=16",
+    # This is the recommendation from
+    # http://users.ece.cmu.edu/~koopman/roses/dsn04/koopman04_crc_poly_embedded.pdf
+    # for messages of 242 - 2048 bits, which covers what we want.
+    # That's an analysis from an exhaustive search of all polynomials for
+    # various CRCs to find the best ones. This is 0xBAAD, converted from the
+    # weird format used there to the standard one used by pycrc.
+    "--poly=0x755b",
+    "--reflect-in=False",
+    "--xor-in=0xffff",
+    "--reflect-out=False",
+    "--xor-out=0xffff",
+    "--std=C99",
+    "--algorithm=table-driven",
+    "--symbol-prefix=jevois_spi_crc_",
+    "--crc-type=uint16_t",
+]
+
+genrule(
+    name = "gen_spi_crc",
+    outs = [
+        "spi_crc.h",
+        "spi_crc.c",
+    ],
+    cmd = " && ".join([
+        " ".join(spi_crc_args + [
+            "--generate=h",
+            "--output=$(location spi_crc.h)",
+        ]),
+        " ".join(spi_crc_args + [
+            "--generate=c",
+            "--output=$(location spi_crc.c)",
+        ]),
+    ]),
+    tools = [
+        "//third_party/pycrc:pycrc_main",
+    ],
+)
+
+cc_library(
+    name = "spi_crc",
+    srcs = [
+        "spi_crc.c",
+    ],
+    hdrs = [
+        "spi_crc.h",
+    ],
+    deps = [
+        "//third_party/GSL",
+    ],
+)
+
 cc_library(
     name = "structures",
     hdrs = [
@@ -9,3 +63,31 @@
         "//third_party/eigen",
     ],
 )
+
+cc_library(
+    name = "spi",
+    srcs = [
+        "spi.cc",
+    ],
+    hdrs = [
+        "spi.h",
+    ],
+    deps = [
+        ":spi_crc",
+        ":structures",
+        "//aos/util:bitpacking",
+        "//third_party/GSL",
+        "//third_party/optional",
+    ],
+)
+
+cc_test(
+    name = "spi_test",
+    srcs = [
+        "spi_test.cc",
+    ],
+    deps = [
+        ":spi",
+        "//aos/testing:googletest",
+    ],
+)
diff --git a/y2019/jevois/spi.cc b/y2019/jevois/spi.cc
new file mode 100644
index 0000000..0500860
--- /dev/null
+++ b/y2019/jevois/spi.cc
@@ -0,0 +1,237 @@
+#include "y2019/jevois/spi.h"
+
+#include <assert.h>
+
+#include "aos/util/bitpacking.h"
+#include "third_party/GSL/include/gsl/gsl"
+#include "y2019/jevois/spi_crc.h"
+
+// SPI transfer format (6x 8 bit frames):
+// 1. 1-byte brightness for each beacon channel.
+// 2. 1-byte specifying on/off for each light ring.
+// 3. 2-byte CRC
+//
+// SPI transfer format (41x 8 bit frames):
+// 1. Camera frame 0
+// 2. Camera frame 1
+// 3. Camera frame 2
+// 4. 2-byte CRC-16
+// Each camera frame (13x 8 bit frames):
+//   1. Duration for how old the frame is. This is a value received from the
+//      camera, added to the time between the first character being received
+//      by the MCU to the CS line being asserted. Specifically it's an 8 bit
+//      unsigned number of ms.
+//   2. Target 0
+//   3. Target 1
+//   4. Target 2
+//   Each target (4x 8 bit frames):
+//     1. 10 bits heading
+//     2. 8 bits distance
+//     3. 6 bits skew
+//     4. 6 bits height
+//     5. 1 bit target valid (a present frame has all-valid targets)
+//     6. 1 bit target present (a present frame can have from 0 to 3
+//          targets, depending on how many were found)
+//   Note that empty frames are still sent to indicate that the camera is
+//   still working even though it doesn't see any targets.
+
+namespace frc971 {
+namespace jevois {
+namespace {
+
+constexpr float heading_min() { return -3; }
+constexpr float heading_max() { return 3; }
+constexpr int heading_bits() { return 10; }
+constexpr int heading_offset() { return 0; }
+void heading_pack(float heading, gsl::span<char> destination) {
+  const auto integer = aos::FloatToIntLinear<heading_bits()>(
+      heading_min(), heading_max(), heading);
+  aos::PackBits<uint32_t, heading_bits(), heading_offset()>(integer,
+                                                            destination);
+}
+float heading_unpack(gsl::span<const char> source) {
+  const auto integer =
+      aos::UnpackBits<uint32_t, heading_bits(), heading_offset()>(source);
+  return aos::IntToFloatLinear<heading_bits()>(heading_min(), heading_max(),
+                                               integer);
+}
+
+constexpr float distance_min() { return 0; }
+constexpr float distance_max() {
+  // The field is 18.4m diagonally.
+  return 18.4;
+}
+constexpr int distance_bits() { return 8; }
+constexpr int distance_offset() { return heading_offset() + heading_bits(); }
+void distance_pack(float distance, gsl::span<char> destination) {
+  const auto integer = aos::FloatToIntLinear<distance_bits()>(
+      distance_min(), distance_max(), distance);
+  aos::PackBits<uint32_t, distance_bits(), distance_offset()>(integer,
+                                                              destination);
+}
+float distance_unpack(gsl::span<const char> source) {
+  const auto integer =
+      aos::UnpackBits<uint32_t, distance_bits(), distance_offset()>(source);
+  return aos::IntToFloatLinear<distance_bits()>(distance_min(), distance_max(),
+                                                integer);
+}
+
+constexpr float skew_min() { return -3; }
+constexpr float skew_max() { return 3; }
+constexpr int skew_bits() { return 6; }
+constexpr int skew_offset() { return distance_offset() + distance_bits(); }
+void skew_pack(float skew, gsl::span<char> destination) {
+  const auto integer =
+      aos::FloatToIntLinear<skew_bits()>(skew_min(), skew_max(), skew);
+  aos::PackBits<uint32_t, skew_bits(), skew_offset()>(integer, destination);
+}
+float skew_unpack(gsl::span<const char> source) {
+  const auto integer =
+      aos::UnpackBits<uint32_t, skew_bits(), skew_offset()>(source);
+  return aos::IntToFloatLinear<skew_bits()>(skew_min(), skew_max(), integer);
+}
+
+constexpr float height_min() { return 0; }
+constexpr float height_max() { return 1.5; }
+constexpr int height_bits() { return 6; }
+constexpr int height_offset() { return skew_offset() + skew_bits(); }
+void height_pack(float height, gsl::span<char> destination) {
+  const auto integer =
+      aos::FloatToIntLinear<height_bits()>(height_min(), height_max(), height);
+  aos::PackBits<uint32_t, height_bits(), height_offset()>(integer, destination);
+}
+float height_unpack(gsl::span<const char> source) {
+  const auto integer =
+      aos::UnpackBits<uint32_t, height_bits(), height_offset()>(source);
+  return aos::IntToFloatLinear<height_bits()>(height_min(), height_max(),
+                                              integer);
+}
+
+constexpr int valid_bits() { return 1; }
+constexpr int valid_offset() { return height_offset() + height_bits(); }
+void valid_pack(bool valid, gsl::span<char> destination) {
+  aos::PackBits<uint32_t, valid_bits(), valid_offset()>(valid, destination);
+}
+bool valid_unpack(gsl::span<const char> source) {
+  return aos::UnpackBits<uint32_t, valid_bits(), valid_offset()>(source);
+}
+
+constexpr int present_bits() { return 1; }
+constexpr int present_offset() { return valid_offset() + valid_bits(); }
+void present_pack(bool present, gsl::span<char> destination) {
+  aos::PackBits<uint32_t, present_bits(), present_offset()>(present,
+                                                            destination);
+}
+bool present_unpack(gsl::span<const char> source) {
+  return aos::UnpackBits<uint32_t, present_bits(), present_offset()>(source);
+}
+
+constexpr int next_offset() { return present_offset() + present_bits(); }
+static_assert(next_offset() <= 32, "Target is too big");
+
+}  // namespace
+
+SpiTransfer SpiPackToRoborio(const TeensyToRoborio &message) {
+  SpiTransfer transfer;
+  gsl::span<char> remaining_space = transfer;
+  for (int frame = 0; frame < 3; ++frame) {
+    for (int target = 0; target < 3; ++target) {
+      remaining_space[0] = 0;
+      remaining_space[1] = 0;
+      remaining_space[2] = 0;
+      remaining_space[3] = 0;
+
+      if (static_cast<int>(message.frames.size()) > frame) {
+        valid_pack(true, remaining_space);
+        if (static_cast<int>(message.frames[frame].targets.size()) > target) {
+          heading_pack(message.frames[frame].targets[target].heading,
+                       remaining_space);
+          distance_pack(message.frames[frame].targets[target].distance,
+                        remaining_space);
+          skew_pack(message.frames[frame].targets[target].skew,
+                    remaining_space);
+          height_pack(message.frames[frame].targets[target].height,
+                      remaining_space);
+          present_pack(true, remaining_space);
+        } else {
+          present_pack(false, remaining_space);
+        }
+      } else {
+        valid_pack(false, remaining_space);
+      }
+
+      remaining_space = remaining_space.subspan(4);
+    }
+    if (static_cast<int>(message.frames.size()) > frame) {
+      const uint8_t age_count = message.frames[frame].age.count();
+      memcpy(&remaining_space[0], &age_count, 1);
+    } else {
+      remaining_space[0] = 0;
+    }
+    remaining_space = remaining_space.subspan(1);
+  }
+  {
+    uint16_t crc = jevois_spi_crc_init();
+    crc = jevois_spi_crc_update(crc, transfer.data(),
+                                transfer.size() - remaining_space.size());
+    crc = jevois_spi_crc_finalize(crc);
+    assert(static_cast<size_t>(remaining_space.size()) >= sizeof(crc));
+    memcpy(&remaining_space[0], &crc, sizeof(crc));
+    remaining_space = remaining_space.subspan(sizeof(crc));
+  }
+  assert(remaining_space.empty());
+  return transfer;
+}
+
+tl::optional<TeensyToRoborio> SpiUnpackToRoborio(const SpiTransfer &transfer) {
+  TeensyToRoborio message;
+  gsl::span<const char> remaining_input = transfer;
+  for (int frame = 0; frame < 3; ++frame) {
+    const bool have_frame = valid_unpack(remaining_input);
+    if (have_frame) {
+      message.frames.push_back({});
+    }
+    for (int target = 0; target < 3; ++target) {
+      if (present_unpack(remaining_input)) {
+        if (have_frame) {
+          message.frames.back().targets.push_back({});
+          message.frames.back().targets.back().heading =
+              heading_unpack(remaining_input);
+          message.frames.back().targets.back().distance =
+              distance_unpack(remaining_input);
+          message.frames.back().targets.back().skew =
+              skew_unpack(remaining_input);
+          message.frames.back().targets.back().height =
+              height_unpack(remaining_input);
+        }
+      }
+
+      remaining_input = remaining_input.subspan(4);
+    }
+    if (have_frame) {
+      uint8_t age_count;
+      memcpy(&age_count, &remaining_input[0], 1);
+      message.frames.back().age = camera_duration(age_count);
+    }
+    remaining_input = remaining_input.subspan(1);
+  }
+  {
+    uint16_t calculated_crc = jevois_spi_crc_init();
+    calculated_crc =
+        jevois_spi_crc_update(calculated_crc, transfer.data(),
+                              transfer.size() - remaining_input.size());
+    calculated_crc = jevois_spi_crc_finalize(calculated_crc);
+    uint16_t received_crc;
+    assert(static_cast<size_t>(remaining_input.size()) >= sizeof(received_crc));
+    memcpy(&received_crc, &remaining_input[0], sizeof(received_crc));
+    remaining_input = remaining_input.subspan(sizeof(received_crc));
+    if (calculated_crc != received_crc) {
+      return tl::nullopt;
+    }
+  }
+  assert(remaining_input.empty());
+  return message;
+}
+
+}  // namespace jevois
+}  // namespace frc971
diff --git a/y2019/jevois/spi.h b/y2019/jevois/spi.h
new file mode 100644
index 0000000..e0c4d90
--- /dev/null
+++ b/y2019/jevois/spi.h
@@ -0,0 +1,34 @@
+#ifndef Y2019_JEVOIS_SPI_H_
+#define Y2019_JEVOIS_SPI_H_
+
+#include <stdint.h>
+
+#include <array>
+
+#include "third_party/optional/tl/optional.hpp"
+#include "y2019/jevois/structures.h"
+
+// This file manages serializing and deserializing the various structures for
+// transport via SPI.
+//
+// Our SPI transfers are fixed-size to simplify everything.
+
+namespace frc971 {
+namespace jevois {
+
+constexpr size_t spi_transfer_size() {
+  // The teensy->RoboRIO side is way bigger, so just calculate that.
+  return 3 /* 3 frames */ *
+             (1 /* age */ + 3 /* targets */ * 4 /* target size */) +
+         2 /* CRC-16 */;
+}
+static_assert(spi_transfer_size() == 41, "hand math is wrong");
+using SpiTransfer = std::array<char, spi_transfer_size()>;
+
+SpiTransfer SpiPackToRoborio(const TeensyToRoborio &message);
+tl::optional<TeensyToRoborio> SpiUnpackToRoborio(const SpiTransfer &transfer);
+
+}  // namespace jevois
+}  // namespace frc971
+
+#endif  // Y2019_JEVOIS_SPI_H_
diff --git a/y2019/jevois/spi_test.cc b/y2019/jevois/spi_test.cc
new file mode 100644
index 0000000..de5158f
--- /dev/null
+++ b/y2019/jevois/spi_test.cc
@@ -0,0 +1,110 @@
+#include "y2019/jevois/spi.h"
+
+#include <stdint.h>
+
+#include "gtest/gtest.h"
+
+namespace frc971 {
+namespace jevois {
+namespace testing {
+
+// Tests packing and then unpacking an empty message.
+TEST(SpiToRoborioPackTest, Empty) {
+  TeensyToRoborio input_message;
+  const SpiTransfer transfer = SpiPackToRoborio(input_message);
+  const auto output_message = SpiUnpackToRoborio(transfer);
+  ASSERT_TRUE(output_message);
+  EXPECT_EQ(input_message, output_message.value());
+}
+
+// Tests that unpacking after the message has been modified results in a
+// checksum failure.
+TEST(SpiToRoborioPackTest, CorruptChecksum) {
+  TeensyToRoborio input_message;
+  {
+    SpiTransfer transfer = SpiPackToRoborio(input_message);
+    transfer[0]++;
+    ASSERT_FALSE(SpiUnpackToRoborio(transfer));
+  }
+  {
+    SpiTransfer transfer = SpiPackToRoborio(input_message);
+    transfer[0] ^= 0xFF;
+    ASSERT_FALSE(SpiUnpackToRoborio(transfer));
+  }
+  {
+    SpiTransfer transfer = SpiPackToRoborio(input_message);
+    transfer[transfer.size() - 1]++;
+    ASSERT_FALSE(SpiUnpackToRoborio(transfer));
+  }
+  input_message.frames.push_back({});
+  {
+    SpiTransfer transfer = SpiPackToRoborio(input_message);
+    transfer[0]++;
+    ASSERT_FALSE(SpiUnpackToRoborio(transfer));
+  }
+  {
+    SpiTransfer transfer = SpiPackToRoborio(input_message);
+    transfer[3]++;
+    ASSERT_FALSE(SpiUnpackToRoborio(transfer));
+  }
+  input_message.frames.back().targets.push_back({});
+  {
+    SpiTransfer transfer = SpiPackToRoborio(input_message);
+    transfer[3]++;
+    ASSERT_FALSE(SpiUnpackToRoborio(transfer));
+  }
+}
+
+// Tests packing and then unpacking a full message.
+TEST(SpiToRoborioPackTest, Full) {
+  TeensyToRoborio input_message;
+  input_message.frames.push_back({});
+  input_message.frames.back().age = camera_duration(9);
+  input_message.frames.push_back({});
+  input_message.frames.back().age = camera_duration(7);
+  input_message.frames.push_back({});
+  input_message.frames.back().age = camera_duration(1);
+
+  const SpiTransfer transfer = SpiPackToRoborio(input_message);
+  const auto output_message = SpiUnpackToRoborio(transfer);
+  ASSERT_TRUE(output_message);
+  EXPECT_EQ(input_message, output_message.value());
+}
+
+// Tests that packing and unpacking a target results in values close to before.
+TEST(SpiToRoborioPackTest, Target) {
+  TeensyToRoborio input_message;
+  input_message.frames.push_back({});
+  input_message.frames.back().targets.push_back({});
+  input_message.frames.back().targets.back().distance = 9;
+  input_message.frames.back().targets.back().height = 1;
+  input_message.frames.back().targets.back().heading = 0.5;
+  input_message.frames.back().targets.back().skew = -0.5;
+  input_message.frames.push_back({});
+  input_message.frames.back().targets.push_back({});
+  input_message.frames.back().targets.push_back({});
+  input_message.frames.push_back({});
+  input_message.frames.back().targets.push_back({});
+  input_message.frames.back().targets.push_back({});
+  input_message.frames.back().targets.push_back({});
+
+  const SpiTransfer transfer = SpiPackToRoborio(input_message);
+  const auto output_message = SpiUnpackToRoborio(transfer);
+  ASSERT_TRUE(output_message);
+  ASSERT_EQ(3u, output_message->frames.size());
+  ASSERT_EQ(1u, output_message->frames[0].targets.size());
+  ASSERT_EQ(2u, output_message->frames[1].targets.size());
+  ASSERT_EQ(3u, output_message->frames[2].targets.size());
+  EXPECT_NEAR(input_message.frames.back().targets.back().distance,
+              output_message->frames.back().targets.back().distance, 0.1);
+  EXPECT_NEAR(input_message.frames.back().targets.back().height,
+              output_message->frames.back().targets.back().height, 0.1);
+  EXPECT_NEAR(input_message.frames.back().targets.back().heading,
+              output_message->frames.back().targets.back().heading, 0.1);
+  EXPECT_NEAR(input_message.frames.back().targets.back().skew,
+              output_message->frames.back().targets.back().skew, 0.1);
+}
+
+}  // namespace testing
+}  // namespace jevois
+}  // namespace frc971
diff --git a/y2019/jevois/structures.h b/y2019/jevois/structures.h
index d2ab3e5..c82a089 100644
--- a/y2019/jevois/structures.h
+++ b/y2019/jevois/structures.h
@@ -41,6 +41,25 @@
 // just use floats and not worry about it.
 
 struct Target {
+  bool operator==(const Target &other) const {
+    if (other.distance != distance) {
+      return false;
+    }
+    if (other.height != height) {
+      return false;
+    }
+    if (other.heading != heading) {
+      return false;
+    }
+    if (other.skew != skew) {
+      return false;
+    }
+    return true;
+  }
+  bool operator!=(const Target &other) const {
+    return !(*this == other);
+  }
+
   // Distance to the target in meters. Specifically, the distance from the
   // center of the camera's image plane to the center of the target.
   float distance;
@@ -65,6 +84,19 @@
 //
 // This is all the information sent from each camera to the Teensy.
 struct Frame {
+  bool operator==(const Frame &other) const {
+    if (other.targets != targets) {
+      return false;
+    }
+    if (other.age != age) {
+      return false;
+    }
+    return true;
+  }
+  bool operator!=(const Frame &other) const {
+    return !(*this == other);
+  }
+
   // The top most interesting targets found in this frame.
   aos::SizedArray<Target, 3> targets;
 
@@ -74,14 +106,34 @@
 
 // This is all the information sent from the Teensy to each camera.
 struct CameraCalibration {
+  bool operator==(const CameraCalibration &other) const {
+    if (other.calibration != calibration) {
+      return false;
+    }
+    return true;
+  }
+  bool operator!=(const CameraCalibration &other) const {
+    return !(*this == other);
+  }
+
   // The calibration matrix. This defines where the camera is pointing.
   //
-  // TODO(Parker): What are the details on how this is defined.
+  // TODO(Parker): What are the details on how this is defined?
   Eigen::Matrix<float, 3, 4> calibration;
 };
 
 // This is all the information the Teensy sends to the RoboRIO.
 struct TeensyToRoborio {
+  bool operator==(const TeensyToRoborio &other) const {
+    if (other.frames != frames) {
+      return false;
+    }
+    return true;
+  }
+  bool operator!=(const TeensyToRoborio &other) const {
+    return !(*this == other);
+  }
+
   // The newest frames received from up to three cameras. These will be the
   // three earliest-received of all buffered frames.
   aos::SizedArray<Frame, 3> frames;
@@ -89,6 +141,19 @@
 
 // This is all the information the RoboRIO sends to the Teensy.
 struct RoborioToTeensy {
+  bool operator==(const RoborioToTeensy &other) const {
+    if (other.beacon_brightness != beacon_brightness) {
+      return false;
+    }
+    if (other.light_rings != light_rings) {
+      return false;
+    }
+    return true;
+  }
+  bool operator!=(const RoborioToTeensy &other) const {
+    return !(*this == other);
+  }
+
   // Brightnesses for each of the beacon light channels. 0 is off, 255 is fully
   // on.
   std::array<uint8_t, 3> beacon_brightness;
diff --git a/y2019/wpilib_interface.cc b/y2019/wpilib_interface.cc
index c696a37..bc6c25f 100644
--- a/y2019/wpilib_interface.cc
+++ b/y2019/wpilib_interface.cc
@@ -169,9 +169,9 @@
 
     ::frc971::wpilib::DrivetrainWriter drivetrain_writer;
     drivetrain_writer.set_left_controller0(
-        ::std::unique_ptr<::frc::VictorSP>(new ::frc::VictorSP(2)), false);
+        ::std::unique_ptr<::frc::VictorSP>(new ::frc::VictorSP(0)), true);
     drivetrain_writer.set_right_controller0(
-        ::std::unique_ptr<::frc::VictorSP>(new ::frc::VictorSP(3)), false);
+        ::std::unique_ptr<::frc::VictorSP>(new ::frc::VictorSP(1)), false);
     ::std::thread drivetrain_writer_thread(::std::ref(drivetrain_writer));
 
     // Wait forever. Not much else to do...