Technology Resources

A Guide to Choosing LEDs for Paper Circuits

Paper circuits are a fun way to gain some circuitry skills while letting your creativity get a little exercise. If you are thinking of doing something with paper circuits, you might be wondering which LEDs will work best for your project.

I have experimented with three types of LEDs and here is a brief description and review of each:

Circuit StickersChibitronics Stickers

If you are looking for something easy to use and that will reliably make a connection, consider Chibitronics circuit stickers. They have some drawbacks, but they work better than any other option I have tested.

Pros:

  • They work really well with any copper tape project. In my opinion, these are the best lights to use for any paper circuit project.
  • They are easy for kids to use.
  • They have built-in resistors.

Cons:

  • Colors must be bought as sets. The company just added 3 more colors which is nice, but the stickers are sold in sets of either red, yellow, blue or orange, purple and green. White is the only color that can be purchased on its own.
  • They are expensive. Each sticker is about four times the cost of a standard LED.
  • The packaging is a problem. They can only be purchased in sets of 30 lights, 10 each of three colors, except for white. White leds are sold in sets of 30 lights. The packaging is also excessive. When you buy 30 lights, they come in a molded plastic holder with a plastic film sealing the lights in place. This is then sealed again on the back with cardboard. The lights are slightly more fragile because they come off their backing easily, but this seems like overkill and it has to raise the cost of the lights.

Etextile lightsLilypad and Sequin e-textile lights

The two types of e-textile lights that I have evaluated are made by Sparkfun and Adafruit. The Sparkfun lights are called Lilypad LEDs and the Adafruit lights are called Sequins.

Pros:

  • They come in lots of colors and, unlike the Chibitronic lights, you can by them one color at a time.
  • They are very durable and reusable. All you have to do is rip them off one project and use them on another. They can even be washed!
  • They have built-in resistors.

Cons:

  • It is hard to get a good connection on paper circuits. They don’t slip off as easily as standard LEDs, but they are rigid so they don’t bend with paper. These would be a perfect light if it weren’t for the connection problem.

Standard LEDs Standard LED

These are the lights you see with the long legs. LEDs are polarized, and with the Standard lights the positive side is the one with the longer leg.

Pros

  • They are cheap. A pack of 20 lights can be purchased for under $3.
  • They come in a lot of colors.
  • They are readily available.

Cons

  • The legs break easily. Be careful handing these out to a roomful of grade school kids without clear instructions on where and how to bend them. Even then, there is a good chance kids will break them.
  • Standard LEDs will use as much electricity as you give them, to the point of burning themselves out. To keep this from happening, you need a resistor placed in the circuit to regulate the amount of electricity getting to the LED.
  • When using them for paper circuits, they need to be taped to your conductive surface (copper tape for my kits). It may look easy, but getting the legs of the LED to stay on the copper tape, even when taped onto it, is difficult. The LED legs aren’t as flexible as most papers so the contacts are poor and the lights may not stay lit.

If you want to know more about LEDs in general, Sparkfun has a tutorial to get you started.