Use an AVR Microcontroller and Potentiometer to Control a Servo (ADC and PWM) http://youtu.be/vNwx_W2daJs

gistfile1.cpp

#define F_CPU 16000000 //16MHz
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <stdlib.h>

//#include <stdio.h>
//#include "uart/uart.h"


#define PWM_PRESCALLER 64
#define ICR_MAX (long double)F_CPU/PWM_PRESCALLER/50
#define OCR_MIN ICR_MAX/20
#define OCR_MAX ICR_MAX/10

//char uart_s[150];
volatile unsigned long adc_val=0;
volatile unsigned long counter=0;
unsigned long curr_adc=0;

ISR (ADC_vect)
{
	adc_val += ADC;
	counter++;
}

int main(void)
{
	//uart_init(uart_calc_ubrr(F_CPU));
	
	DDRB |= (1<<DDB1);
	
	ICR1 = ICR_MAX;
	OCR1A = OCR_MIN;
	TCCR1A = (1 << COM1A1) | (1<<WGM11);
	TCCR1B = (1<<WGM13) | (1<<WGM12) | (1<<CS11) | (1<<CS10);
	
	
	
	ADMUX = (1 << REFS0);
	ADCSRA = (1 << ADEN)|(1 << ADFR)|(1 << ADIE)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);
	
	sei();
	
	ADCSRA |= (1<<ADSC);
	


	while(1)
	{
		if(counter >= 500)
		{
			cli();
			
			unsigned long round_val = round(adc_val / counter);
			
			adc_val=0;
			counter=0;
			
			if(abs(round_val - curr_adc) > 1)
			{
				curr_adc = round_val;
			}
			
			long double ocr = OCR_MIN + ((long double)curr_adc * (OCR_MAX - OCR_MIN)/1024);
			
			/*sprintf(uart_s, "ADC = %8lu, OCR = %f, rounded = %d\r\n", curr_adc, ocr, (int)round(ocr));
			uart_send_string((unsigned char*) uart_s);*/
			
			OCR1A = (int)round(ocr);
			
			//_delay_ms(100);
			sei();
		}
	}
}