Macdonald Nwabia / Mbed 2 deprecated ElderPlus_SecuritySystem

2nd year embedded systems project

Dependencies:   mbed C12832

Diff: Door_1_Docs/hcsr04.cpp

Revision:
1:9d7c34bfe43e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Door_1_Docs/hcsr04.cpp	Tue Dec 15 18:15:48 2020 +0000
@@ -0,0 +1,29 @@
+#include "hcsr04.h"
+#include "mbed.h"
+/*
+*HCSR04.cpp
+*/
+HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {}
+ float HCSR04::echo_duration() {
+        
+    timer.reset();  //reset timer
+    trig=0;   // trigger low 
+    wait_us(2); //  wait 
+    trig=1;   //  trigger high
+    wait_us(10);
+    trig=0;  // trigger low
+         while(!echo); // start pulseIN
+      timer.start();
+     while(echo);
+      timer.stop();
+     return timer.read_us(); 
+ 
+}
+ 
+//return distance in cm 
+float HCSR04::distance(){
+    duration = echo_duration();
+  distance_cm = (duration/2)/29.1  ;
+        return distance_cm;
+ 
+}
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