/*
  
  ESP8266 Wemos by Kevin Wieland for EVNotiPi
  adjusted by Mario Mueller
  Recognizes voltage above 12.75V and turns Relay on (Rpi).
  Shutdown and turns off
  Relay Hat on Wemos D1 Mini.
  D0 to GPIO24 Rpi
  A0 with 1.2MOhm resistor to +12V
  
*/
#include <ESP8266WiFi.h>
const int relayPin = D1;
const int shutdownPin = D0;
int pistat = 0;
int counter = 0;
void setup() {
  Serial.begin(9600);
  pinMode(relayPin, OUTPUT);
  pinMode(shutdownPin, OUTPUT);
  digitalWrite(shutdownPin, LOW);
  WiFi.mode(WIFI_OFF);
  WiFi.forceSleepBegin();
}
void loop() {
  delay(2000); 
  int sensorValue = analogRead(A0);
  float voltage = sensorValue * (0.0144);
  Serial.print("Sensor Value: ");
  Serial.println(sensorValue);
  Serial.print("Voltage: ");
  Serial.println(voltage);                  
  if ( voltage > 12.75 )
  {
    if ( pistat == 0 )
    {
      counter == 0;
      Serial.println("Power up Rpi");
      digitalWrite(relayPin, HIGH);
      delay(60000 );
      pistat = 1;
    } 
  }
  else
  {
      if ( pistat == 1)
      {
        counter = counter + 1;
        Serial.print("Counter: ");
        Serial.println(counter);
        if ( counter > 150 )
        {
          Serial.println("initiate sutdown");
          digitalWrite(shutdownPin, HIGH);
          delay(3000);
          digitalWrite(shutdownPin, LOW);
          delay(40000);
          counter = 0;
          Serial.println("Rpi off"); 
          digitalWrite(relayPin, LOW);
          pistat = 0;
        }
      }
   }
}