Here is the source code I am using.
#include "SoR_Utils.h" //includes all the technical stuff
int main(void)
{
//declare variables here
//int i=250;//a 'whatever' variable
int sensor_left=0;//left photoresistor
int sensor_right=0;//right photoresistor
int threshold=8;//the larger this number, the more likely your robot will drive straight
/****************INITIALIZATIONS*******************/
//other stuff Im experimenting with for SoR
//uartInit(); // initialize the UART (serial port)
//uartSetBaudRate(9600);// set the baud rate of the UART for our debug/reporting output
//rprintfInit(uartSendByte);// initialize rprintf system
//timerInit(); // initialize the timer system
configure_ports(); // configure which ports are analog, digital, etc.
a2dInit(); // initialize analog to digital converter (ADC)
a2dSetPrescaler(ADC_PRESCALE_DIV32); // configure ADC scaling
a2dSetReference(ADC_REFERENCE_AVCC); // configure ADC reference voltage
//rprintf("Initialization Complete\r\n");
/**************************************************/
/*********ADD YOUR CODE BELOW THIS LINE **********/
LED_off();//turn LED on
while(1)
{
//store sensor data
sensor_left=a2dConvert8bit(5);
sensor_right=a2dConvert8bit(4);
//detects more light on left side of robot
if(sensor_left > sensor_right && (sensor_left - sensor_right) > threshold)
{//go left
servo_left(44);
servo_right(44);
}
//detects more light on right side of robot
else if(sensor_right > sensor_left && (sensor_right - sensor_left) > threshold)
{//go right
servo_left(25);
servo_right(25);
}
//light is about equal on both sides
else
{//go straight
servo_left(25);
servo_right(44);
}
/* Servo Test Code
int i=0;
i=250;
while(i>0)
{
servo_left(40);
i--;
}
i=250;
while(i>0)
{
servo_left(24);
i--;
}*/
//rprintf("Initialization Complete\r\n");
//output message to serial (use hyperterminal)
//print("Hello, World! Read My Analog: %u\r\n", sensor_0);
delay_cycles(500);//a small delay to prevent crazy oscillations
}
/*********ADD YOUR CODE ABOVE THIS LINE **********/
return 0;
}
/*********************COMMAND LIST*************************
delay_cycles(cycles);
Delays - you can make your robot wait for a certain amount of time with this function.
Put the number of computational cycles to delay in the ().
23 cycles is about .992 milliseconds
to calculate: 23/.992*(time in milliseconds to delay) = cycles
Check servo datasheet where it says: 'Direction: Clockwise/Pulse Traveling 1500 to 1900usec'
servo_left(speed); and servo_right(speed);
Commands your servos to rotate at a certain speed.
Vary speed (which represents a delay in cycles) from 20 to 50.
Left is for port D0 and right is for port D1.
LED_on(); and LED_off();
Turns on and off your LED. The LED is on port D4.
By bringing port D4 low, you are turning on the LED.
variable=a2dConvert8bit(pin);
Reads analog pin. For example, set 'pin' to 5 to read PC5.
'variable' will store the value.
***********************************************************/