Diff: main.cpp

Revision:

0:c5c22fd71be8

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Oct 27 16:42:08 2013 +0000
@@ -0,0 +1,61 @@
+/* This program uses Christopher Hasler motor library to derive DC motors */
+
+#include "mbed.h"
+#include "motordriver.h"
+
+// Array of Motor type objects to define 4 motors for two bots.
+Motor M[]= {Motor(p25, p9, p8, 1), Motor(p26, p11, p10, 1), Motor(p21, p13, p12, 1), Motor(p22, p15, p14, 1)};
+// Array acc defines 4 analogin type objects to detect inputs of accelerometer.
+AnalogIn acc[]= {p16, p17, p19, p18};
+/*@update reads recent values from accelerometer and uses them to control motors
+  @param 'a' tell for which bot the vales should be updated( a=0 for 1st bot and a=2 for 2nd bot)
+*/
+int update(int a)
+{
+    float offx=0, offy=0, map=0, turnp=0, turnn=0;
+    /*output votage of accelerometer at x and y outs when x=0 and y=0;
+      turnp and turnn specifies the positive and negative voltage difference(CurrentVoltage - offset) detected from offset value when accelerometer is tilted.
+      I will be using turnp and turnn as the minimum required voltage difference(ie, the minimum required tilt) to turn the bot.
+      The value below are default ones for my accelerometer
+    */
+    if(a==0) {
+        offx=0.340;
+        offy=0.340;
+        turnp=0.032;
+        turnn=0.055;
+        map=14.68;
+    } else if(a==2) {
+        offx=0.350;
+        offy=0.440;
+        turnp=0.040;
+        turnn=0.045;
+        map=13.40;
+    } else
+        return(-1);  // return -1 as error when update is called with unexpected argument value
+    float s=0, st=0; 
+    s=acc[a+1].read();
+    s=(s-offy)*map; // multiply by 'map' to linearly map difference (s-offy) to euivalent scale on 0 to 1 so that s can be used as speed
+                    // (s=0 for (s-offy)=0 and s=1 for max[(s-offy)] )
+    st=acc[a].read();
+    st=st-offx;
+    if(st>0 && abs(st)>turnp) {  // checking whether to turn or not ( st>0: right turn and st<0: left trun)
+        M[a].speed(0);
+        M[a+1].speed(1);
+    } else if(st<0 && abs(st)>turnn) {
+        M[a].speed(1);
+        M[a+1].speed(0);
+    } else {    // if no turn input then run both motors with speed s
+        M[a].speed(s);
+        M[a+1].speed(s);
+    }
+    return 1;
+}
+
+int main()
+{
+    while(1) {
+        update(0);  // Calling update for first bot(a=0) and second bot(a=2)
+        update(2);
+        wait(0.2);
+    }
+}
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