diff --git a/wpilibc/sim/include/Relay.h b/wpilibc/sim/include/Relay.h
new file mode 100644
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--- /dev/null
+++ b/wpilibc/sim/include/Relay.h
@@ -0,0 +1,79 @@
+/*----------------------------------------------------------------------------*/
+/* 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include "LiveWindow/LiveWindowSendable.h"
+#include "MotorSafety.h"
+#include "SensorBase.h"
+#include "simulation/SimContinuousOutput.h"
+#include "tables/ITable.h"
+#include "tables/ITableListener.h"
+
+namespace frc {
+
+class MotorSafetyHelper;
+class DigitalModule;
+
+/**
+ * Class for Spike style relay outputs.
+ *
+ * Relays are intended to be connected to spikes or similar relays. The relay
+ * channels controls a pair of pins that are either both off, one on, the other
+ * on, or both on. This translates into two spike outputs at 0v, one at 12v and
+ * one at 0v, one at 0v and the other at 12v, or two spike outputs at 12V. This
+ * allows off, full forward, or full reverse control of motors without variable
+ * speed.  It also allows the two channels (forward and reverse) to be used
+ * independently for something that does not care about voltage polatiry (like
+ * a solenoid).
+ */
+class Relay : public MotorSafety,
+              public SensorBase,
+              public ITableListener,
+              public LiveWindowSendable {
+ public:
+  enum Value { kOff, kOn, kForward, kReverse };
+  enum Direction { kBothDirections, kForwardOnly, kReverseOnly };
+
+  explicit Relay(int channel, Direction direction = kBothDirections);
+  virtual ~Relay();
+
+  void Set(Value value);
+  Value Get() const;
+  int GetChannel() const;
+
+  void SetExpiration(double timeout) override;
+  double GetExpiration() const override;
+  bool IsAlive() const override;
+  void StopMotor() override;
+  bool IsSafetyEnabled() const override;
+  void SetSafetyEnabled(bool enabled) override;
+  void GetDescription(std::ostringstream& desc) const override;
+
+  void ValueChanged(ITable* source, llvm::StringRef key,
+                    std::shared_ptr<nt::Value> value, bool isNew) override;
+  void UpdateTable() override;
+  void StartLiveWindowMode() override;
+  void StopLiveWindowMode() override;
+  std::string GetSmartDashboardType() const override;
+  void InitTable(std::shared_ptr<ITable> subTable) override;
+  std::shared_ptr<ITable> GetTable() const override;
+
+  std::shared_ptr<ITable> m_table;
+
+ private:
+  int m_channel;
+  Direction m_direction;
+  std::unique_ptr<MotorSafetyHelper> m_safetyHelper;
+  SimContinuousOutput* impl;
+  bool go_pos, go_neg;
+};
+
+}  // namespace frc