// ===================================
// SolarRobot Control software
// Arduino NG version with ATmega 168
//
// Created by E.Dertien  June 3th 2008
//
// for Interactivos?08
// ===================================
// version 1.0      
// In this version the timing is set by potmeter 1, potmeter 2 defines a voltage trigger level
//

// Globals and variables
int timingPotmeter = 1;          // select the input pin for the potentiometer
int triggerLevelPotmeter = 2;    // select the input pin for the potentiometer
int voltageSense =3;             // select the input pin for the voltage divider
int ledHIGH = 3;                 // select the pin for the LED (bi-color, so two pins are being used)
int ledLOW = 2;
int powerOUT = 9;                // select output pin for transistor
int delaytime,n,SolarVoltage = 0;       // variable to store the value coming from the sensor

#define MIN_MOTOR_TRESHOLD 80    //(1/11 voltage divider causes AD resolution of 0.0537 V/bit) The minimum value where a motor still works is hereby set at 4.3 V

//#define SERIALPORT  // if not defined, then the serial routines will not be compiled

void setup() 
{ 
#ifdef SERIALPORT
  Serial.begin(9600); 
  // prints title with ending line break 
  Serial.println("SolarRobot Control software"); 
#endif
  pinMode(ledHIGH, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(ledLOW, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(powerOUT, OUTPUT); // declare transistor pin as output 
  // wait for the long string to be sent 
  delay(100); 
} 
 
 
void loop() 
{ 

 for (n=0;n<250;n++)   // n=100 gives a maximum time interval of 250 * 1023 ms = 255 sec
  {    
      // 
      // voltageSense gives a value of 93 at 5V, 293 at 12V (1/11 voltage divider causes AD resolution of 0.0537 V/bit)
      // if the timer interval just started, and if sensed voltage level is higher than preset level by potentiometer, turn on motor
      // 
      // 
      // the maximum value of analogRead(voltageSense) is 25V (maximum voltage of solarpanel) divided by 0.0537 V/bit = 465 
      // the triggerLevelPotmeter value is maximal 1023, so devididing this value by three maps both ranges better. 
      // still, in time mode the motor is not turned on when the solar voltage is not above the MIN_MOTOR_TRESHOLD value (80*0.537 = 4.2V)
      SolarVoltage = analogRead(voltageSense);
      if ((n==0) && SolarVoltage >((analogRead(triggerLevelPotmeter)/3)+MIN_MOTOR_TRESHOLD))          
      { 
          analogWrite(powerOUT,255);   // turn the motor on. The powerlevel is determined by the solar voltage. 
          digitalWrite(ledHIGH, HIGH);   // sets the LED on
          digitalWrite(ledLOW,LOW);      // turn the LED on
      }
      if ((analogRead(voltageSense))<MIN_MOTOR_TRESHOLD) // when voltage is dropped below absolute motor minimum
      {
          analogWrite(powerOUT,0);   // turn the Motor off
          digitalWrite(ledHIGH, LOW);   // turn the LED off
          digitalWrite(ledLOW,LOW);     // turn the LED off   
      } 
      delay(analogRead(timingPotmeter)); // delay is called 250 times for every period so at max 250 * 1023 msec = 255 sec
  }
}