[LOWCAR] Ultrasonic Sensor Addition

lowcar/devices/Device/defs.h

@@ -60,8 +60,8 @@ enum class DeviceType : uint8_t {
     SERVO_CONTROL = 0x04,
     POLAR_BEAR = 0x05,
     KOALA_BEAR = 0x06,
-    PDB = 0x07
-    // DISTANCE_SENSOR   = 0x07 Uncomment when implemented
+    PDB = 0x07,
+    ULTRASONIC_SENSOR = 0x08
 };
 
 // identification for resulting status types

lowcar/devices/UltrasonicSensor/UltrasonicSensor.cpp

@@ -0,0 +1,32 @@
+#include "UltrasonicSensor.h"
+
+// pin definitions for the ultrasonic sensor
+#define TRIG_PIN 16
+#define ECHO_PIN 14
+
+UltrasonicSensor::UltrasonicSensor() : Device(DeviceType::ULTRASONIC_SENSOR, 17) {
+    ;
+}
+
+size_t UltrasonicSensor::device_read(uint8_t param, uint8_t* data_buf) {
+    // trigger the ultrasonic pulse
+    digitalWrite(TRIG_PIN, LOW);
+    delayMicroseconds(2);
+
+    digitalWrite(TRIG_PIN, HIGH);
+    delayMicroseconds(10);
+    digitalWrite(TRIG_PIN, LOW);
+
+    long duration = pulseIn(ECHO_PIN, HIGH);
+    float distance = duration * 0.034f / 2.0f;  // convert to cm
+
+    float* float_buf = (float*) data_buf;
+    float_buf[0] = distance;
+
+    return sizeof(float);
+}
+
+void UltrasonicSensor::device_enable() {
+    pinMode(TRIG_PIN, OUTPUT);
+    pinMode(ECHO_PIN, INPUT);
+}

lowcar/devices/UltrasonicSensor/UltrasonicSensor.h

@@ -0,0 +1,21 @@
+#ifndef ULTRASONIC_SENSOR_H
+#define ULTRASONIC_SENSOR_H
+
+#include <stdint.h>
+#include "Device.h"
+#include "defs.h"
+
+class UltrasonicSensor : public Device {
+  public:
+    // Constructor
+    UltrasonicSensor();
+
+    virtual size_t device_read(uint8_t param, uint8_t* data_buf);
+    virtual void device_enable();
+
+  private:
+    static uint8_t trigPin;
+    static uint8_t echoPin;
+};
+
+#endif

runtime_util/runtime_util.c

@@ -116,6 +116,13 @@ device_t PDB = {
         {.name = "dv_cell3", .type = FLOAT, .read = 1, .write = 0},
         {.name = "network_switch", .type = BOOL, .read = 1, .write = 0}}};
 
+device_t UltrasonicSensor = {
+    .type = 8,
+    .name = "UltrasonicSensor",
+    .num_params = 1,
+    .params = {
+        {.name = "distance", .type = FLOAT, .read = 1, .write = 0}}};
+
 // *********************** VIRTUAL DEVICE DEFINITIONS *********************** //
 
 // A CustomDevice is unusual because the parameters are dynamic
@@ -216,6 +223,7 @@ __attribute__((constructor)) void devices_arr_init() {
     DEVICES[PolarBear.type] = &PolarBear;
     DEVICES[KoalaBear.type] = &KoalaBear;
     DEVICES[PDB.type] = &PDB;
+    DEVICES[UltrasonicSensor.type] = &UltrasonicSensor;
     DEVICES[CustomDevice.type] = &CustomDevice;
     DEVICES[SoundDevice.type] = &SoundDevice;
     DEVICES[TimeTestDevice.type] = &TimeTestDevice;