Wireless Dual DC Motor Control

The Software
           There are two parts to this software/firmware section:
    -The Controller Transmitter
    -The Receiver Motor Controller



           The transmitter is constantly polling the ADC values from RA0 and RA1, scaling the value and adding it to a single 8 bit data variable. Then, those 8 bits are sent out the USART and to the XBee module at 9600 BPS.

Transmitter Program

..
...
/************* Convert Channel 0 *****************/
OpenADC(ADC_FOSC_32 & ADC_RIGHT_JUST & ADC_20_TAD, 
		ADC_CH0 & ADC_INT_OFF & ADC_VREFPLUS_VDD 
		& ADC_VREFMINUS_VSS, 0);
//Convrt A/D
Delay10TCYx( 5 ); // Delay for 50TCY
ConvertADC(); // Start conversion
//Read A/D
while( BusyADC()); // Wait for completion
	result = (ReadADC()); // Read result
Delay10TCYx(5);
CloseADC(); // Disable A/D converter 
/************* ***************** *****************/

data += (result>>6);

/************* Convert Channel 1 *****************/
OpenADC(ADC_FOSC_32 & ADC_RIGHT_JUST & ADC_20_TAD, 
		ADC_CH1 & ADC_INT_OFF & ADC_VREFPLUS_VDD 
		& ADC_VREFMINUS_VSS, 0);
//Convrt A/D
Delay10TCYx( 5 ); // Delay for 50TCY
ConvertADC(); // Start conversion
//Read A/D
while( BusyADC() ); // Wait for completion
	result = (ReadADC()); // Read result
Delay10TCYx(5);
CloseADC(); // Disable A/D converter 
/************* ***************** *****************/

data += (result&0b1111000000)>>2;

Delay10KTCYx(5);
putcUSART( data ); 	
...
..

           Surprisingly, the receiver firmware is even easier to write. The 8 bit USART command is received, decoded and used to set the PWM duty cycle for each motor individually.

Receiver Program

..
...
	if(DataRdyUSART()){
		data = getcUSART();
		motor1_speed = data&0b00001111;
		motor2_speed = (data&0b11110000)>>4;
	}

	//For Motor #1
	//Scale 500 by 16 using the lower 4 bits of data
	SetDCPWM1((500*(motor1_speed+1))/16);

	//For Motor #2
	//Scale 500 by 16 using the upper 4 bits of data
	SetDCPWM2((500*(motor2_speed+1))/16);

	Delay1KTCYx(1);
... 	
..

           So give the code a compile and download it to your PIC and then when you're ready, let's give it a test run and see how well the system works.