Diff: HCSR04.h

Revision:

0:8871082486ac

Child:

1:9989fcb7f189

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HCSR04.h	Sat Dec 05 09:02:35 2015 +0000
@@ -0,0 +1,57 @@
+#ifndef HCSR04_H_TVZMT
+#define HCSR04_H_TVZMT
+
+/** A distance measurement class using ultrasonic sensor HC-SR04.
+ *  
+ * Example of use:
+ * <<code>>
+ * #include "mbed.h"
+ * #include "HCSR04.h"
+ *
+ * Serial pc(USBTX, USBRX);    // communication with terminal
+ * 
+ * int main() {
+ *     HCSR04 sensor(p5, p7);     // instantiate the sensor object
+ *     while(1) {
+ *         pc.printf("Distance: %5.1f cm\r", sensor.getDistance_cm());
+ *         wait_ms(975); // print the result every 1 second
+ *     }
+ * }
+ * <</code>>
+ */
+class HCSR04 {
+    
+    public:
+    
+    /** Receives two PinName variables.
+     * @param echoPin mbed pin to which the echo signal is connected to
+     * @param triggerPin mbed pin to which the trigger signal is connected to
+     */
+    HCSR04(PinName echoPin, PinName triggerPin);
+    
+    /** Calculates the distance in cm, with the calculation time of 25 ms.
+     * @returns distance of the measuring object in cm.
+     */
+    float getDistance_cm();
+    
+    private:
+    
+    InterruptIn echo;       // echo pin
+    DigitalOut trigger;     // trigger pin
+    Timer timer;            // echo pulsewidth measurement
+    float distance;         // store the distance in cm
+    
+    /** Start the timer. */
+    void startTimer();
+    
+    /** Stop the timer. */
+    void stopTimer();
+    
+    /** Initialization. */
+    void init();
+    
+    /** Start the measurement. */
+    void startMeasurement();
+};
+
+#endif
\ No newline at end of file