3.0 Simple Photocell Project

This project will demonstrate using the Arduino to sense light and dark using a photocell.

Connect your components as follows:

The resisters in series create a Voltage Divider. Our project is going to use Analog pin A0 to read the voltage.

Create an Arduino sketch with the following Code:

Photocell Project
Engineering Period 1

Revision History
DATE  |    NAME    |     Changes Made
TODAY |  My Name   |  Initial Implementation

// the setup routine runs once when you press reset or apply power:
void setup() {
  // initialize serial communication at 9600 bits per second:
  //Set pin A0 For Input - Allow us to read the value
  pinMode(A0, INPUT);


// the loop routine runs over and over again forever:
void loop() {
 // read the input on analog pin 0:
 int sensorValue = analogRead(A0);

 //Send the output to the Serial Port


After you have written your code, compile and upload the code to the Arduino. Once the code has been uploaded to the Arduino, from the tools menu select serial monitor.

  • What values are you seeing?
  • What happens when you cover the photocell?

analogRead() Documentation