This tutorial shows you how to make a card turn on when opened using a light sensor sticker. You can use this to light up an LED, or get creative and use it as a switch to turn on more adventurous circuits!
Here are some examples of wonderful cards by Chibitronics makers.
- light sensor sticker from Circuit Stickers Sensors Add-On
- copper tape
- 3V coin cell battery
- binder clip (or neodymium magnets)
1. Plan your circuit and trace your battery, light sensor and LEDs. Be sure to mark where the signal, positive and negative pads of the light sensor goes. Putting the light sensor closer to the battery, with the positive pad closer to the battery and negative pad closer to the LEDs makes is easier to make the rest of the circuit.
2. Using copper tape, connect the negative pad to the negative side of the battery outline and the negative side of the LED.
3. Finish your circuit by connecting the positive side of the LEDs to the signal pad of the light sensor sticker and positive side of the pad to the positive side of the battery.
4. Stick the light sensor and the LED in their places.
5. Clip the battery into place and test your card. The LED should light up when you open the card and turn off when closed. You can test this by covering the light sensor with your hand.
6. Decorate your card as you wish.
7.If you would like to cover up the circuitry, just poke a hole on the cover paper so the light sensor can be exposed to light. The actual sensor on the sticker is the tiny square in the middle, right above the “LIGHT” text, so your hole can be pretty small.
Image: Light sensor hidden behind photograph
Note: light colored papers, like we used in this tutorial, may not block the light enough for the sensor to work. Use thicker, darker colored paper to make sure no light reaches the sensor when the card is closed.
Note: If you have more than one LED in your circuit, make sure that they are connected in parallel. A coin cell battery is strong not enough for two LEDs in series. For more information, visit the Parallel and Series Connections Tutorial.