Simple electromagnetic field detector with an Arduino

EMFDetector.ino

/*
 * Pin A0 -> 2MΩ resistor -> GND
 * Pin A0 -> antenna (a piece of wire a few centimeters long)
 *
 * Pin 11 -> LED -> 330KΩ resistor -> GND
 */


static const char sensorPin = 0;
static const char ledPin = 11;
static const char samples = 10;


void setup() {
  pinMode(ledPin, OUTPUT);
}


void loop() {
  int sense = 0;
  
  for (int i = 0; i < samples; i++) {
    sense += analogRead(sensorPin);
    delay(2);
  }
  
  sense /= samples;

  sense = constrain(sense, 1, 100);
  sense = map(sense, 5, 100, 0, 255);

  analogWrite(ledPin, sense);

  delay(50);
}