/*
    Arduino Power DC to AC Inverter Power Circuits
    https://www.bristolwatch.com/ele/arduino_power_inverter.htm
    by Lewis Loflin lewis@bvu.net
*/
    
#define MOSFET1  9
#define MOSFET2  10
#define EnablePower 2  // HV power on switch
#define batteryVoltage 0  // Ad0
#define heatSink 1  // Ad1
#define batteryGoodInd 12 
#define fanOnInd 11
#define HVON  13 // high voltage on blinks

int x = 0;  int y = 0; int z = 0;

void setup() {                

  pinMode(MOSFET1, OUTPUT); // MOSFET 1
  pinMode(MOSFET2, OUTPUT);  // MOSFET 2

  pinMode(EnablePower, INPUT); // N.O. switch
  digitalWrite(EnablePower, HIGH); // pull up enabled
  
  pinMode(HVON, OUTPUT);
  digitalWrite(HVON, LOW);
  
  pinMode(batteryGoodInd, OUTPUT);
  digitalWrite(batteryGoodInd, LOW);

  pinMode(fanOnInd, OUTPUT);
  digitalWrite(fanOnInd, LOW);

}

void loop() {
  y = analogRead(batteryVoltage);
  if (y > 150) digitalWrite(batteryGoodInd, LOW);  
// battery LED off
     else digitalWrite(batteryGoodInd, HIGH);  
// battery too low LED on
     
     
  if (analogRead(heatSink) > 500) digitalWrite(fanOnInd, HIGH); 
// cooling fan on
    else digitalWrite(fanOnInd, LOW); 

// cooling fan off  
     
  if ((digitalRead(EnablePower) == 0) && (y > 150))  {   
// check for closed enable switch, battery state
    SoftStart();  // bring power up slowly
    while ((digitalRead(EnablePower) == 0) && (y > 150))   {
      digitalWrite(MOSFET1, HIGH);   // MOSFET1 on
      delayMicroseconds(360);
      delay(8);  // wait for 8.3 mS
      digitalWrite(MOSFET1, LOW);  // MOSFET1 off

      digitalWrite(MOSFET2, HIGH);   // MOSFET2 on
      delayMicroseconds(360);
      delay(8);  // wait for 8.3 mS
      digitalWrite(MOSFET2, LOW);  // MOSFET2 off

      x++;
      if (x == 20) { // flash HVON LED
        toggle(HVON);
        y = analogRead(0); 
        x=0;
        if (analogRead(heatSink) > 500) digitalWrite(fanOnInd, HIGH); 
// cooling fan on
           else digitalWrite(fanOnInd, LOW);
// cooling fan off 
      } // end 2nd if

    } // end while

  } // 

}  // end loop


void toggle(int pinNum) {  
// toggle the state on a pin

  int pinState = digitalRead(pinNum);
  pinState = !pinState;
  digitalWrite(pinNum, pinState); 
}

//SoftStart allows power to come up slowly to prevent excessive surges
// time is about 2 seconds


void SoftStart(void)   {
  int y = 2;
  int x = 0;
  int z = 6;
  while (y < 8)   {

    digitalWrite(MOSFET1, HIGH);   // MOSFET1 on
    delayMicroseconds(360);
    delay(y);  // wait for 8.3 mS
    digitalWrite(MOSFET1, LOW);  // MOSFET1 off
    delay(z);

    digitalWrite(MOSFET2, HIGH);   // MOSFET2 on
    delayMicroseconds(360);
    delay(y);  // wait for 8.3 mS
    digitalWrite(MOSFET2, LOW);  // MOSFET2 off
    delay(z);

    x++;
    if (x == 30) { 
      y = y + 2;
      z = z - 2; 
      x=0;

    }
  }
}