/*

  Several changes to the original sketch from post #1 in the forum
  see code for comments

  Forum: https://forum.arduino.cc/t/potentiometer-change-threshold-value/1155150/6
  Wokwi: https://wokwi.com/projects/372327961938093057


*/

#define SHUTTER_PIN 2
#define LIGHTNING_TRIGGER_ANALOG_PIN 0
#define TRIGGER_THRESHHOLD 18

int lightningVal;

void setup()
{
  pinMode(SHUTTER_PIN, OUTPUT);
  digitalWrite(SHUTTER_PIN, LOW);
  Serial.begin(9600); // open serial

  // Use mapping here as well to avoid triggering after (re-)start of the sketch
  lightningVal = map(analogRead(LIGHTNING_TRIGGER_ANALOG_PIN), 0, 1023, 0, 50);
  Serial.print("Starting with lightningVal:\t");
  Serial.println(lightningVal);
}

void loop()
{
  // Added mapping here from 0..1023 to 0..50 also
  int aLightningVal = analogRead(LIGHTNING_TRIGGER_ANALOG_PIN);
  int newLightningVal = map(aLightningVal, 0, 1023, 0, 50);

  if (abs(newLightningVal - lightningVal) > TRIGGER_THRESHHOLD)
  {
    // Moved the prints here so that they are readable before the
    // delay
    Serial.println("Shutter triggered");
    // Moved this line from below the if-clause to here so
    // that the variable lightningVal is only changed if
    // the condition above was true
    lightningVal = newLightningVal;
    Serial.print("New lightningVal:\t");
    Serial.println(lightningVal, DEC);
    digitalWrite(SHUTTER_PIN, HIGH);
    delay(1000); // May want to adjust this depending on shot type
    digitalWrite(SHUTTER_PIN, LOW);
  }
}