Diff: main.cpp

Revision:

0:d9625740c0f9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Dec 10 15:16:02 2015 +0000
@@ -0,0 +1,104 @@
+#include "mbed.h"
+SPI ser_port(p11, p12, p13);    // mosi, miso, sclk, ssel
+DigitalOut cs(p14);        //this acts as “slave select”  
+Serial pc(USBTX, USBRX);
+DigitalIn echo(p20);
+DigitalOut trigger(p19);
+DigitalIn echo1(p18);
+DigitalOut trigger1(p17);
+DigitalIn echo2(p16);
+DigitalOut trigger2(p15);
+DigitalOut greenled(p21);
+DigitalOut redled(p22);
+DigitalOut yellowled(p23);
+char switch_word ; //word we will send
+
+Timer t;
+float i,j,k;
+
+int main() 
+{
+    ser_port.format(8,0); 
+    ser_port.frequency(4000000); 
+    t.start(); //start timer  
+    while(1) 
+    {
+        trigger = 1;
+        wait_ms(1); 
+        trigger=0; //stop sending pulses 
+        while(!echo); //listen for echo pulse 
+        t.reset(); //reset timer to measure echo pulse width 
+        while(echo); 
+        i=t.read_us(); //attach i to echo pulse width of sensor 1 in us
+         
+        trigger1 = 1;
+        wait_ms(1); 
+        trigger1=0; //stop sending pulses 
+        while(!echo1); //listen for echo pulse 
+        t.reset(); //reset timer to measure echo pulse width 
+        while(echo1); 
+        j=t.read_us(); //attach i to echo pulse width of sensor 1 in us
+        
+        trigger2 = 1;
+        wait_ms(1); 
+        trigger2=0; //stop sending pulses 
+        while(!echo2); //listen for echo pulse 
+        t.reset(); //reset timer to measure echo pulse width 
+        while(echo2); 
+        k=t.read_us(); //attach i to echo pulse width of sensor 1 in us
+
+        i=i/58; //converting to cm
+        j=j/58;
+        k=k/58;
+        pc.printf("Distance of i\n\r");
+        pc.printf("%1.3f \n\r",i);
+        wait(0.10);
+        pc.printf("Distance of j\n\r");
+        pc.printf("%1.3f \n\r",j);
+        wait(0.10);
+        pc.printf("Distance of k\n\r");
+        pc.printf("%1.3f \n\r",k);
+        wait(0.10);
+        
+        greenled = 0; 
+        redled = 0; 
+        yellowled = 0;
+        
+        switch_word=0xF0; //set up a recognisable output pattern
+        if((i>95) &&(j>95)&&(k>95)){ // condition for no obstacle
+        switch_word=switch_word|0x00; //move forward
+        }
+        if((i<95)&&(j>95)&&(k>95)){ //sensor 1 senses obstacle
+        switch_word=switch_word|0x01; // obstacle in the centre; turn left
+        yellowled=1;
+        }
+        if ((j<95)&&(i>95)&&(k>95)){
+        switch_word=switch_word|0x02; // obstacle on the right; turn left
+        greenled=1;
+        }
+        if((k<95)&&(j>95)&&(i>95)){
+        switch_word=switch_word|0x03; // obstacle on the left; turn right
+        redled=1;
+        }
+        if((i<95)&&(j<95)&&(k<95)){
+        switch_word= switch_word|0x04; // no way clear; reverse
+        greenled=1;
+        redled=1;
+        yellowled=1;
+        }
+        if((i<95)&&(j<95)&&(k>95)){
+        switch_word= switch_word|0x05; // FR
+        greenled=1;
+        yellowled=1;
+        }
+        if((i<95)&&(k<95)&&(j>95)){
+        switch_word= switch_word|0x06; // FL
+        redled=1;
+        yellowled=1;
+        }
+        cs = 0;                                //select slave
+        ser_port.write(switch_word);  //send switch_word
+        cs = 1;                 
+        wait (0.000002);
+    }
+}
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