Intro: LED Birthday Card
Step 1: Materials
You don't need much to get started. I think the more crafty you are the better, that way you'll not only have a card the lights up but looks pretty too!
- copper tape (local hardware store or electronics store should have it)
- LED (any size and color)
- 3V coin cell battery (I use CR2032)
- scotch tape
- colored pencils, tissue paper, etc. (stuff to make it look nice)
**NB: if you can't find or afford copper tape, aluminum tape works just as well and costs less.
Step 2: Design Your Circuit
I find it helps to draw your circuit it first so you know where your LEDs will be placed and how you'll lay out your tape. My design for this card was inspired by blowing out a birthday candle. The LED will light up when you hold a button saying, "make a wish," then you blow out the candle (and release the button), the LED goes OFF and your wish comes true!
Here's my design, but you can design anything! If you're going to use more than one LED, I suggest a parallel circuit design. I've found my circuit designs work best with no more than 3 LEDs per battery.
Step 3: Measure Length of Tape Needed
This is important because the more breaks you have the weaker the current will be and your light won't work.
For this specific project, I used three pieces of copper tape:
- 1 piece of copper tape that ran from one lead of my LED to the battery
- then 1 piece that ran from my battery to the switch
- and finally 1 piece that ran from the switch to the other lead of my LED
**NB: You can solder to the copper tape, so if you have a break you can reinforce it with solder. Just be careful not to start a fire or burn your card. If you can't solder or don't want to risk it, make sure when extending a piece of tape, you sandwich the two pieces together. Simply laying them on top of each other is not enough to carry the full current.
Step 4: Prepare the LED
The longer lead of the LED is the "+" positive lead and should connect to the "+" positive side of your battery.
Bend this lead up and into a circle
The shorter lead of the LED is the "-" negative lead and should connect to the "-" negative side of your battery.
Bend this lead up and into a square
Step 5: Prepare Battery Holder & Switch
I'm using the battery holder template designed by Jie Qi of the MIT Media Lab. She has two great websites with tutorials on how to fold the tape using her battery holder and examples of card templates you can use. I found both to be great "getting started" resources.
Paper Battery Holder Tutorial
Paper Electronics Template Cards
Step 6: Make Your Circuit & Enjoy!
using the copper tape, connect your LED "+" poisitve lead to the positive side of your battery
then connect your battery's "-" negative side to another piece of copper tape, extending it out to create one side of the switch
finally, with a third strip of copper tape, complete your switch and connect the tape to the "-" negative lead of your LED