Photoreceptor LED Light

This tutorial will show you how to connect a photoreceptor to an Arduino board.

A photoreceptor is just a fancy word for a light sensor. When light input is high, the LED bulb shines brighter. When light input is low, the LED bulb dims. For example, at night, electricity will be conserved by using lower lights when bright lights are not needed.

In this project we are placing the light in a birdhouse. The lights will react to whether or not light is shining in through the windows / from a flashlight. A real world use for this technology is the reduced usage of electricity in homes. If you need to leave a light on at night, it will automatically be dimmer and use fewer volts.

Step 1: Suggested Materials

OIn order to complete this project, you will need the following materials;

Arduino Uno: This board is a simpler arduino that can be used to program commands to an LED light. We are using this in tandem with a SIK tutorial.

Jumper wires: 6 are needed for this project.
Photoreceptor: This is senstitive to light and will affect the brightness of the bulb.

LED light: 1 is needed for this project.

Resistors: 2 are needed for this project.

Step 2: Arduino Setup

Once you have replicated the diagram above, attach your arduino to a power source (in this instance, a laptop computer), verify then upload the code. This code was provided by the Arduino SIK Guide, and it will be supplied below.

To test the light senstitivity, place your finger over the photoreceptor and watch the LED light. If the light dims when you cover up the receptor, you've set it up correctly.

Step 3: The Birdhouse

For our project, we placed the photoreceptor in a birdhouse for a small scale version of how it would save energy in a full sized home. We built it out of wood pieces and cut windows for light to stream through.

1. You will need enough wood for four walls, a floor, and a roof. We used a tape measurer to cut four pieces for the walls: two pairs for each parallel wall.

2. For the roof, we cut small rectangles using the power saw and placed them overlapping so that light (in our case) or water (in real life) could not seep through.

3. The windows were cut using a machine.

Step 4: The Experiment

In order to test the photoreceptor in the new environment, we kept the arduino isolated from light and monitored the LED output. When a phone flashlight shone through, the light dimmed and the output decreased.