Grant Phillips
Class library for a HC-SR04 Distance Sensor based on PwmOut (Trig) and InterruptIn (Echo).
Dependents: ultra TDPS-COM1 HCSR04
Diff: HCSR04.cpp
- Revision:
- 0:5541303b14e7
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/HCSR04.cpp Mon Feb 08 14:43:42 2016 +0000
@@ -0,0 +1,28 @@
+#include "HCSR04.h"
+#include "mbed.h"
+
+
+HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {
+ trig.period(0.06);
+ trig.pulsewidth_us(20);
+ echo.rise(this,&HCSR04::HighTrigger);
+ echo.fall(this,&HCSR04::LowTrigger);
+}
+
+unsigned int HCSR04::read_us() {
+ return us;
+}
+
+float HCSR04::read_cm() {
+ return (float)us/58;
+}
+
+void HCSR04::HighTrigger() {
+ timer.start();
+}
+
+void HCSR04::LowTrigger() {
+ timer.stop();
+ us = timer.read_us();
+ timer.reset();
+}
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