diff --git a/wpilibc/athena/src/GearTooth.cpp b/wpilibc/athena/src/GearTooth.cpp
new file mode 100644
index 0000000..210f12d
--- /dev/null
+++ b/wpilibc/athena/src/GearTooth.cpp
@@ -0,0 +1,69 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008-2017. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "GearTooth.h"
+
+#include "LiveWindow/LiveWindow.h"
+
+using namespace frc;
+
+constexpr double GearTooth::kGearToothThreshold;
+
+/**
+ * Common code called by the constructors.
+ */
+void GearTooth::EnableDirectionSensing(bool directionSensitive) {
+  if (directionSensitive) {
+    SetPulseLengthMode(kGearToothThreshold);
+  }
+}
+
+/**
+ * Construct a GearTooth sensor given a channel.
+ *
+ * @param channel            The DIO channel that the sensor is connected to.
+ *                           0-9 are on-board, 10-25 are on the MXP.
+ * @param directionSensitive True to enable the pulse length decoding in
+ *                           hardware to specify count direction.
+ */
+GearTooth::GearTooth(int channel, bool directionSensitive) : Counter(channel) {
+  EnableDirectionSensing(directionSensitive);
+  LiveWindow::GetInstance()->AddSensor("GearTooth", channel, this);
+}
+
+/**
+ * Construct a GearTooth sensor given a digital input.
+ *
+ * This should be used when sharing digital inputs.
+ *
+ * @param source             A pointer to the existing DigitalSource object
+ *                           (such as a DigitalInput)
+ * @param directionSensitive True to enable the pulse length decoding in
+ *                           hardware to specify count direction.
+ */
+GearTooth::GearTooth(DigitalSource* source, bool directionSensitive)
+    : Counter(source) {
+  EnableDirectionSensing(directionSensitive);
+}
+
+/**
+ * Construct a GearTooth sensor given a digital input.
+ *
+ * This should be used when sharing digital inputs.
+ *
+ * @param source             A reference to the existing DigitalSource object
+ *                           (such as a DigitalInput)
+ * @param directionSensitive True to enable the pulse length decoding in
+ *                           hardware to specify count direction.
+ */
+GearTooth::GearTooth(std::shared_ptr<DigitalSource> source,
+                     bool directionSensitive)
+    : Counter(source) {
+  EnableDirectionSensing(directionSensitive);
+}
+
+std::string GearTooth::GetSmartDashboardType() const { return "GearTooth"; }