Variable resistor control LED Dimmer use PIC Microcontroller and Mikro C

In this tutorial we will learn how to LED brightness control use variable resistor. Here I am use PIC16F877A Microcontroller.

You can watch the video or read the written tutorial below.

PIC16F877A Microcontroller has two CCP module. CCP means Capture Compare Pulse Width Modulation. It generate different duty cycle pulse. The Analog output voltage of microcontroller depend on duty cycle. When duty cycle 0% than output voltage of CCP is 0 volt , duty cycle 50% output voltage 2.5 volt and duty cycle 100% out is 5 volt.

Circuit Diagram

In this project I am use Analog Channel 0 for analog voltage input. The output of CCP module depend on input analog voltage. When increase the input analog voltage the output of Duty Cycle increase. The Duty Cycle is proportional of input Analog voltage.

Mikro C Code:

	int i = 0;
	float j =0;
	float ADC_Value;
	void main() {
	TRISA = 0XFF; // PORTA is input
	PORTA = 0X00; // Clear PORTA
	ADC_Init(); // Initialize ADC module
	PWM1_Init(1000); // Initialize PWM1 at 1KHz
	PWM1_Start(); // Start PWM1
	while(1){ // Endless loop
	ADC_Value = ADC_Read(0);
	ADC_Value = ADC_Value * 4.89;
	ADC_Value = ADC_Value /1000;
	i = ADC_Value * 20 ;
	j = (i*255)/100;
	// calculate the duty cycle for Pusle Width Modulation
	//duty cycle = (percent of duty cycle*255)/100;
	PWM1_Set_Duty(j);
	}

	}