Week 9b – Analog Input & Output

// NOTE: to make a voltage divider for the photo resistor (which you need)
// use a 10k ohm resistor

void setup() {
  // begin the serial connection at 9600 bits per second
  // (the baud rate)
  Serial.begin(9600);
  // for analog output connect to any of the PWM pins
  // these all have a tilda beside the pin number (~)
  pinMode(5, OUTPUT);
}

void loop() {
  // read the potentiometer on analog input pin A0
  int potValue = analogRead(A0); // analog read gives values in a maximum range of 0-1023
  // map the values from the potentiometer from 0-1023 
  // into the range of an analog write (0-255)
  int mappedPotValue = map(potValue, 0, 1023, 0, 255);
  
  // read the photocell on analog input pin A1
  int lightValue = analogRead(A1);

  // print out the light value so we know the range
  Serial.println(lightValue);
  
  // based on the lowest and the highest numbers from the sensor, 
  // map those to the analogWrite range
  // for example, if the lowest number is 500 nd the highest is 900 
  // then do:
  int mappedLightValue = map(lightValue, 500, 900, 0, 255);

  // sometimes the numbers might go lower or higher than 500 or 900
  // it's important to constrain the mapped value 
  //to never go lower than 0 and never higher than 255
  int constrainedValue = constrain(mappedLightValue, 0, 255);

  // finally, take the number from the photocell, that was mapped,
  // and then constrained, and use that for the call to analogWrite
  analogWrite(5, constrainedValue);//0-255
}