Glowing Badge

Make a Circuit

Let’s create your first circuit!

  • Take a regular LED (one with two legs rather than a sewable one) and connect it to a battery by holding both legs to the battery, one on either side. Notice that one of the legs of the LED is longer than the other one. The longer one should be connected to the side of the battery marked with a plus sign +. Watch your LED light up!

My LED didn’t light up

  • If it didn’t work, check that the legs are the right way round.
  • Once you have the LED lighting up, try flipping the battery over so the legs are connected the wrong way around, with the shorter one on the + side of the battery. Does it still work?

How it works

In every circuit, there are a positive or + and a negative or – direction.

For electricity to flow, you need to match up the + to + and the – to – between your components. This is why the LED doesn’t light up when you flip the battery around.

Identifying + and – on different LEDs

  • On the LED, the longer leg is + and the shorter pin is –. You can also identify – by looking closely at the bulb: it is the side with the flat edge.

  • A sewable LED is built onto a tiny printed circuit board, so it has holes instead of legs. The holes are marked with + and – signs.

  • Separate the LED and the battery, and pop the battery into a battery holder, with the + facing up (the holder will have a mark to show its + side too).

  • Get two pieces of conductive thread, and team up with the Ninja next to you, so you can help each other hold things in place.

  • Put one end of the first thread through the + hole of the battery holder, making sure it touches the metal, and hold the other end to the positive leg of the LED. You can use tape if you need to, although this will fray the thread a lot. If you have crocodile clips, you can use these instead of thread.

  • Now take the second thread. Put one end through the – hole of the battery holder, and hold the other end to the negative leg of the LED.

  • Make sure the two threads are not touching or crossing over at any point. If they do, this will cause a short in your circuit and it will not work properly.

What is a short?

  • When you have a short circuit, the electricity goes a shorter way through the circuit, skipping some of the components, and that’s why it stops working.

Now you have a circuit and are ready to make a light-up badge!

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