[wpilib, examples] Cleanup PotentiometerPID, Ultrasonic, UltrasonicPID examples (#4893)

Fix C++ Ultrasonic to return correct units.

wpilibc/src/main/native/cpp/Ultrasonic.cpp

@@ -85,10 +85,7 @@ int Ultrasonic::GetEchoChannel() const {
 }
 
 void Ultrasonic::Ping() {
-  if (m_automaticEnabled) {
-    throw FRC_MakeError(err::IncompatibleMode,
-                        "cannot call Ping() in automatic mode");
-  }
+  SetAutomaticMode(false);  // turn off automatic round-robin if pinging
 
   // Reset the counter to zero (invalid data now)
   m_counter.Reset();
@@ -138,7 +135,7 @@ void Ultrasonic::SetAutomaticMode(bool enabling) {
 units::meter_t Ultrasonic::GetRange() const {
   if (IsRangeValid()) {
     if (m_simRange) {
-      return units::meter_t{m_simRange.Get()};
+      return units::inch_t{m_simRange.Get()};
     }
     return m_counter.GetPeriod() * kSpeedOfSound / 2.0;
   } else {

wpilibc/src/main/native/cpp/simulation/UltrasonicSim.cpp

@@ -9,8 +9,11 @@
 
 using namespace frc::sim;
 
-UltrasonicSim::UltrasonicSim(const frc::Ultrasonic& ultrasonic) {
-  frc::sim::SimDeviceSim deviceSim{"Ultrasonic", ultrasonic.GetEchoChannel()};
+UltrasonicSim::UltrasonicSim(const frc::Ultrasonic& ultrasonic)
+    : UltrasonicSim(0, ultrasonic.GetEchoChannel()) {}
+
+UltrasonicSim::UltrasonicSim(int ping, int echo) {
+  frc::sim::SimDeviceSim deviceSim{"Ultrasonic", echo};
   m_simRangeValid = deviceSim.GetBoolean("Range Valid");
   m_simRange = deviceSim.GetDouble("Range (in)");
 }
@@ -19,6 +22,6 @@ void UltrasonicSim::SetRangeValid(bool isValid) {
   m_simRangeValid.Set(isValid);
 }
 
-void UltrasonicSim::SetRange(units::meter_t range) {
+void UltrasonicSim::SetRange(units::inch_t range) {
   m_simRange.Set(range.value());
 }

wpilibc/src/main/native/include/frc/simulation/UltrasonicSim.h

@@ -14,16 +14,24 @@ class Ultrasonic;
 namespace sim {
 
 /**
- * Class to control a simulated ADXRS450 gyroscope.
+ * Class to control a simulated {@link Ultrasonic}.
  */
 class UltrasonicSim {
  public:
   /**
-   * Constructs from a ADXRS450_Gyro object.
+   * Constructor.
    *
-   * @param gyro ADXRS450_Gyro to simulate
+   * @param ultrasonic The real ultrasonic to simulate
    */
-  explicit UltrasonicSim(const Ultrasonic& gyro);
+  explicit UltrasonicSim(const Ultrasonic& ultrasonic);
+
+  /**
+   * Constructor.
+   *
+   * @param ping unused.
+   * @param echo the ultrasonic's echo channel.
+   */
+  UltrasonicSim(int ping, int echo);
 
   /**
    * Sets if the range measurement is valid.
@@ -37,7 +45,7 @@ class UltrasonicSim {
    *
    * @param range The range
    */
-  void SetRange(units::meter_t range);
+  void SetRange(units::inch_t range);
 
  private:
   hal::SimBoolean m_simRangeValid;