Diff: main.cpp

Revision:

0:8c140b332a82

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Sep 28 14:51:04 2015 +0000
@@ -0,0 +1,94 @@
+#include "mbed.h"
+#include "QEI.h"
+#include "MODSERIAL.h"
+//#include <"math.h">
+
+QEI motor1(D13,D12,NC, 624);
+MODSERIAL pc(USBTX,USBRX);
+DigitalOut direction1(D7);
+PwmOut speed1(D6);
+DigitalIn button1(PTC6);
+
+int main()
+{
+   DigitalOut led(LED_RED);
+   pc.baud(115200);
+   int activation=0;//int for starting calibration
+   float cycle = 0.6;//define the speed of the motor
+   int first = 0;
+   while(1){
+       if (button1.read()==0){
+       activation = 1;//acivate the int if the button is pressed
+       }
+    
+    //pc.printf("%d\n",activation);//test if the button is activated
+    //wait(1);
+    
+   if(activation == 1){
+       DigitalOut led(LED_BLUE);
+       direction1.write(false);//turn motor CCW or CW if set to 0
+   //motor CW = 0
+   //motor CCW = 1
+       speed1.period_us(100);//Set period of PWM to 100 us.
+       speed1.write(cycle);//write the speed to the motor
+            
+       
+       if(first==0){//on the first loop wait a moment for the motor to start.
+           wait(3);
+           first=1;
+           }
+           //set up the speed calculation of the motor
+       wait(0.1);
+       int pos1=motor1.getPulses();
+       //pc.printf("position 1 is: %d\n",pos1);//print position 1
+       wait(0.1);
+       int pos2=motor1.getPulses();
+       //pc.printf("position 2 is: %d\n",pos2);//print position 1
+       int diff = pos2 - pos1;//check if the encoder count stops changing
+       int rads = abs(diff/0.1);
+       pc.printf("the speed is : %d counts/second\n", rads);//print out the speed
+       if(diff == 0){
+           cycle=0;//speed of 0 to stop motor
+           speed1.write(cycle);//write the new speed to the motor
+           motor1.reset();//reset the motor position
+           int posnew=motor1.getPulses();
+           pc.printf("The new position is: %d\n",posnew);
+           activation=0;
+           break;
+       }
+       }
+}
+}
+       //determine speed of movement from the encoder signal
+       // the amount of counts for one revolution is 32
+       //this is X2 encodng, as the QEI uses X2 by default 
+       //and the motor encoder has a X4 encoder and thus 64 counts per revolution
+       //thus keeping in mind the gearbox with 1:131,25 gear ratio:
+       // the amount of counts for a gearbox revolution or resolution is 8400
+       // a revolution is 2 pi rad, resolution is : 8400/2 pi = 1336.90 counts/rad
+       //or for the encoder x2 its 668,45 counts/rad
+ /*      
+   Rotational position in degrees can be calculated by:
+ *
+ * (pulse count / X * N) * 360
+ *
+ * Where X is the encoding type [e.g. X4 encoding => X=4], and N is the number
+ * of pulses per revolution.
+ *
+ * Linear position can be calculated by:
+ *
+ * (pulse count / X * N) * (1 / PPI)
+ *
+ * Where X is encoding type [e.g. X4 encoding => X=44], N is the number of
+ * pulses per revolution, and PPI is pulses per inch, or the equivalent for
+ * any other unit of displacement. PPI can be calculated by taking the
+ * circumference of the wheel or encoder disk and dividing it by the number
+ * of pulses per revolution.
+ 
+     * Reset the encoder.
+     *
+     * Sets the pulses and revolutions count to zero.
+     
+    void reset(void);
+ */
+   
\ No newline at end of file