/*
 * Arduino code for Relay timer with potentiometer
 * This Arduino sketch makes it possible to control a relay with a set time
 * which is set by the potentiometer.
 * Watch video instruction for this code: https://youtu.be/6DGQhQgr7Ak
 * 
 * Written by Ahmad Shamshiri for Robojax.com on Sunday, October 11, 2018 
 * at 15:29 in Ajax, Ontario, Canada
  * 
 * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.
 * This code has been downloaded from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#define relayPin 8 // the pin relay is connected
#define potPin  A0 // the pin potentiometer is connected
#define resetPin 3 // the pin where reset switch is connected
#define startPin 2 // the pin where start switch is connected

#define relayType 'L' // Relay trigger type. L for low and H for high

//because the time below is in milliseconds, 1000ms=1 second, 1000x60=60000 is 1 minute. 60x60x1000=3600000 is 1 hour
const long maxTime = 30000;// maximum timer time in milliseconds. for one minute =60000, 1 hour =3600000
const long minTime = 3000; // minimum timer time in milliseconds

// do not change anything below here
long duration;
int potValue;
long rememTime;
int relayState =0;

void setup() {
  pinMode(relayPin, OUTPUT);// define relayPin  as output
  pinMode(resetPin, INPUT_PULLUP);// define input pin with pullup (watch video)
  pinMode(startPin, INPUT_PULLUP);// define input pin with pullup (watch video)
  attachInterrupt(digitalPinToInterrupt(resetPin), reset, LOW);
    
  Serial.begin(9600);// initialize serial monitor with 9600 baud
  if(relayType == 'L')
  {
    digitalWrite(relayPin, HIGH);// turn the relay OFF and keep it OFF
      Serial.println("Robojax.com Relay Timer"); 
      Serial.println("Relay Type: LOW Trigger");      
  }else{
    digitalWrite(relayPin, LOW);// turn the relay OFF and keep it OFF
      Serial.println("Robojax.com Relay Timer"); 
      Serial.println("Relay Type: HIGH Trigger");
  }  
}

void loop() {
  potValue = analogRead(potPin)/10;// reads the value of the potentiometer (value between 0 and 1023)

  duration = map(potValue, 0, 102, minTime, maxTime);// convert A0 value to time set at minTime and maxTime
  
    if(digitalRead(startPin) ==LOW)
    {
     rememTime = millis();
     relayState = 1;
     controlRelay();// send command to turn the relay ON
    }
   if(  (millis()- rememTime) > duration )
   {
    relayState = 0;
    controlRelay();
   }
      Serial.print("Time: ");
      Serial.print(duration/1000);
      Serial.println(" Seconds");     
 delay(200); // wait for 200 milliseconds    
}// loop end


/*
 * 
 * @brief Turns the relay ON or OFF 
 * @param none
 * @return no return value
 */

 void controlRelay()
 {
  if(relayType == 'L')
  {
     if(relayState == 1)
     {
    digitalWrite(relayPin, LOW);// Turn ON relay
      Serial.print("LT-Relay ON for ");
      Serial.print(duration/1000);// display in seconds
      Serial.println(" Seconds");
     }else{
    digitalWrite(relayPin, HIGH); // turn OFF
      Serial.println("====Relay is OFF");
     }
      
  }else{
     if(relayState == 1)
     {    
      digitalWrite(relayPin, HIGH);
      Serial.print("HT-Relay ON for ");
      Serial.print(duration/1000);// display in seconds
      Serial.println(" Seconds");  
     }else{
      digitalWrite(relayPin, LOW); 
      Serial.println("==Relay OFF");  
     }  
  }

}//controlRelay end




void reset()
{
  duration =0;
   if(relayType == 'L')
  {
    digitalWrite(relayPin, HIGH);// turn OFF High trigger relay     
  }else{
    digitalWrite(relayPin, LOW);// turn OFF Low trigger relay
  
  } 
  Serial.println("Relay OFF"); 

}//reset()