diff --git a/y2018/constants.cc b/y2018/constants.cc
new file mode 100644
index 0000000..42872b9
--- /dev/null
+++ b/y2018/constants.cc
@@ -0,0 +1,106 @@
+#include "y2018/constants.h"
+
+#include <inttypes.h>
+#include <math.h>
+#include <stdint.h>
+
+#include <map>
+
+#if __has_feature(address_sanitizer)
+#include "sanitizer/lsan_interface.h"
+#endif
+
+#include "aos/common/logging/logging.h"
+#include "aos/common/mutex.h"
+#include "aos/common/network/team_number.h"
+#include "aos/once.h"
+
+#include "y2018/control_loops/drivetrain/drivetrain_dog_motor_plant.h"
+#include "y2018/control_loops/drivetrain/polydrivetrain_dog_motor_plant.h"
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+namespace y2018 {
+namespace constants {
+namespace {
+
+const uint16_t kCompTeamNumber = 971;
+const uint16_t kPracticeTeamNumber = 9971;
+
+const Values *DoGetValuesForTeam(uint16_t team) {
+  Values *const r = new Values();
+  Values::Intake *const intake = &r->intake;
+  Values::Proximal *const proximal = &r->proximal;
+  Values::Distal *const distal = &r->distal;
+
+  switch (team) {
+    // A set of constants for tests.
+    case 1:
+      r->down_error = 0;
+      r->vision_name = "test";
+      r->vision_error = -0.030;
+      intake->left_pot_offset = 0;
+      intake->right_pot_offset = 0;
+      proximal->pot_offset = 0;
+      distal->pot_offset = 0;
+      break;
+
+    case kCompTeamNumber:
+      r->down_error = 0;
+      r->vision_name = "competition";
+      r->vision_error = 0.0;
+      intake->left_pot_offset = 0;
+      intake->right_pot_offset = 0;
+      proximal->pot_offset = 0;
+      distal->pot_offset = 0;
+      break;
+
+    case kPracticeTeamNumber:
+      r->down_error = 0;
+      r->vision_name = "practice";
+      r->vision_error = 0.0;
+      intake->left_pot_offset = 0;
+      intake->right_pot_offset = 0;
+      proximal->pot_offset = 0;
+      distal->pot_offset = 0;
+      break;
+
+    default:
+      LOG(FATAL, "unknown team #%" PRIu16 "\n", team);
+  }
+
+  return r;
+}
+
+const Values *DoGetValues() {
+  uint16_t team = ::aos::network::GetTeamNumber();
+  LOG(INFO, "creating a Constants for team %" PRIu16 "\n", team);
+  return DoGetValuesForTeam(team);
+}
+
+}  // namespace
+
+const Values &GetValues() {
+  const Values &r = *DoGetValues();
+  return r;
+}
+
+const Values &GetValuesForTeam(uint16_t team_number) {
+  static ::aos::Mutex mutex;
+  ::aos::MutexLocker locker(&mutex);
+
+  static ::std::map<uint16_t, const Values *> values;
+
+  if (values.count(team_number) == 0) {
+    values[team_number] = DoGetValuesForTeam(team_number);
+#if __has_feature(address_sanitizer)
+    __lsan_ignore_object(values[team_number]);
+#endif
+  }
+  return *values[team_number];
+}
+
+}  // namespace constants
+}  // namespace y2018