Fade.ino

/* 
 * Fade - Using a pressure sensor to fade an LED on.
 * @author Gareth Foote & Berit Greinke
 * 12th November 2015
 */
 
int sensorPin = 1;    // The number of the input pin for the pressure sensor
int ledPin = 0;       // The number of the output pin for the LED

void setup() {
  // Tell the Gemma that the LED pin is an output
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // Read the value of the pressure sensor (variable resistor).
  // analogRead() returns a range of values.
  // The value increases the more pressure is 
  // applied to our sensor.
  int sensorReading = analogRead(sensorPin);

  // The range of values we get from our sensorReading 
  // will vary depending on the resistance of our pressure 
  // sensor. We estimate that the range is approximately 
  // between 0 and 50 depending on the pressure sensor.
  
  // The LED brightness is controlled by passing a value 
  // between 0 and 255. We therefore need to convert/map our 
  // sensorReading to this range.
  int brightness = map(sensorReading, 0, 50, 0, 255);
  brightness = min(brightness, 255);

  // We then tell the ledPin to turn on at this brightness.
  analogWrite(ledPin, brightness);
  
  delay(100);
}