//picmicrolab.com
//Arduino Photoresistor Relay Control with PCF8591 Module

#include "Wire.h"
#define PCF8591 (0x90 >> 1)
byte AdcRead0, AdcRead1, AdcRead2, AdcRead3;//AdcRead1 = LDR,AdcRead3 = Potentiometer
 
void setup()
{
 Wire.begin();
 pinMode(7, OUTPUT); 
}
 
void loop()
{
 Wire.beginTransmission(PCF8591);
 Wire.write(0x04);
 Wire.endTransmission();
 Wire.requestFrom(PCF8591, 5);
 
 AdcRead0=Wire.read();
 AdcRead0=Wire.read();
 AdcRead1=Wire.read();
 AdcRead2=Wire.read();
 AdcRead3=Wire.read();

 
 delay(100);
 if(AdcRead3 < AdcRead1)
 digitalWrite(7, LOW);
 if(AdcRead3 > AdcRead1)
 digitalWrite(7, HIGH);
}