// ----- VoltGuard project ------
// A 5v DTDP relay protects dual probe inputs.
// display DC/AC voltage in default mode (via a R divider & bridge rectifier).
// on button press if voltage across the two probes exceeds a set voltage the device tries to discharge it (assuming it is a charged C.)
// if/when voltage falls below a set voltage it activates relay and the signature capture starts, then hands back to Voltguard, de activates relay.
// waits for button (re)press.
// thus ensuring the input pins used by sigAnalyser never gets zapped by a high voltage.
// buzzer/speaker er pin 3 used as audible progress/status indicater.

//...........................................................................................
// Define the pin numbers for easier reference
// if sharing with sigAnalyser, free pins are: d2,d3,d4,d5,d6,d7,A2,A3, keep A4 & A5 free for I2C
const int buttonPin = 2;    // 'sample' Button connected to digital pin D7 / GND
const int buzzer = 3; //  buzzer or speaker (active or passive?) (D3 is a PWM pin)
const int discharge = 4;   // Digital pin D8, extra discharge R
const int handoff = 5;   // Digital pin D9, indicates handoff/ Relay control/coil
const int analogPin = A2;   // Analog input pin just for voltGuard
int buttonLastState = LOW;  // button state for button logic

//--- SETUP -------------------------------------------------------------------------------------
void setup() {
  // Start serial communication at 115200 bits per second
  Serial.begin(115200);

  // Configure the digital pins
  pinMode(buttonPin, INPUT_PULLUP); // Set D7 as input with internal pull-up resistor
  pinMode(discharge, OUTPUT);       // Set D8 as input, to go low for extra discharge
  pinMode(handoff, OUTPUT);      // Set D9 as output indicates handoff
  pinMode(buzzer, OUTPUT);
  
  // Initialize D9 to LOW
  //digitalWrite(discharge, HIGH);// diagnostic flash only
  //digitalWrite(handoff, HIGH);
  //delay(1000);
  digitalWrite(discharge, LOW);
  digitalWrite(handoff, LOW);
  delay(1000);
}
//==== LOOP ======================================================================================
void loop() {
  // Main loop monitors the voltage on A0 and uses button logic to call signature capture function

  if (digitalRead(buttonPin) == HIGH) {
    buttonLastState = HIGH;// set button state for button logic
    digitalWrite(handoff, LOW);// handoff indicate off
    digitalWrite(discharge, LOW);// extra discharge R off
  }
  float voltage = analogRead(analogPin) * (5.0 / 1023.0); // Convert analog reading to voltage

  // Print the voltage to the Serial Monitor
  Serial.print("Voltage on A0: ");
  Serial.println(voltage);
  delay(200);

  // Check if the button is pressed (buttonPin will read LOW when pressed due to pull-up resistor)
  if ((digitalRead(buttonPin) == LOW) && (buttonLastState == HIGH)) {// new button press event?
    Serial.print("new button press event. ");

    if (voltage > 2.0) {
      digitalWrite(discharge, LOW);// make sure extra discharge R is off
    }

    if (voltage <= 2.0) {
      digitalWrite(discharge, HIGH);// enable extra discharge R
      Serial.print("extra discharge R added  ");
    }

    if (voltage < 1.0) {
      digitalWrite(handoff, HIGH);// handoff indicate
      Serial.print(" handoff... ");

      delay(3000);// proxy for function call to activate relay and do signature capture

      Serial.println(" handback ");
      buttonLastState = LOW;// set button state for button logic (need to wait to take finger off button)
      digitalWrite(handoff, LOW);// clean up ; handoff indicate off
      digitalWrite(discharge, LOW);// clean up ; extra discharge R off
    }
  }

}
//=== LOOP END ========================================================================================
// Function Definitions