Diff: Ranger.cpp

Revision:

0:5871422998cd

diff -r 000000000000 -r 5871422998cd Ranger.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Ranger.cpp	Tue Jun 14 13:33:39 2016 +0000
@@ -0,0 +1,36 @@
+#include "Ranger.h"
+
+
+
+// IO bits for the rangefinder
+DigitalOut trig(PTD7);
+DigitalIn echo(PTD6);
+// timer to handle rangefinder 
+Timer t;
+
+int range(){
+    int rangecm=0,rtime=0;
+    
+    // reset thetimer to zero
+      t.reset();
+    
+
+        //send a trigger pulse
+        trig=1;
+        wait_us(12);
+        trig=0;
+        wait_us(12);
+        trig=1; // thing starts on trigger going high NB - this is buffered with an npn and is connected to its base. high on this pin
+        // sets the actual trigger pin to low and low on this pin sets it to high - this is becausethe ranger needs 5V for high
+        // wait for echo to go high
+        while(echo==0);
+        t.start();
+        while(echo==1 && t.read_us()<58*300); // wait for echo to go low again or for about 3m of range
+        t.stop();
+        rtime=t.read_us();
+        t.reset();
+        rangecm=rtime/58; // convert time in us to range in cm
+        return rangecm; // return range in cm
+    
+    
+    }
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