This project shows how to make some simple lights using a LED, two button/watch batteries, masking tape and a binder clip. Light Emitting Diodes (LED) are useful because of their low power consumption, durability, and low heat.

The small lights can easily be placed on your jacket or hat. They will help people see you when you cycle while it is dark outside.

Step 1: The Parts

The common items:
1, A small metal binder clip
2. masking tape (other types of tape would work but I find masking tape easy to use)

Less common items:
1. LEDs (the yellow and red were my choice) A package of 20 assorted LEDs at Radioshack goes for about $3.00. But if you are serious about lowering your cost buy the LEDs online. There are many online suppliers. The Electronic Goldmine site (interesting site I plan to use soon) had various packages of LEDs. You want T1 type and I think 5mm size is good. I believe the red, amber and green are the cheapest.
2. Small batteries. These battery are used for travel clocks and lately they show up in those musical greeting cards. I bought an off-brand pack of 24 for about $3.00.

So depend on the quantities purchased you should be able to make the lights for less than a $1 each.

Note the positive lead of the LED is slightly longer than the negative lead. The positive and negative leads must be connected correctly for the LED to light.

Step 2: Assemble the Parts

After placing the LED on a piece of masking tape so that the leads are close to the edge of the tape, place the batteries on the leads.
Each battery is 1.5 volts so two batteries are needed to light the LED.
The positive side (+) is typically labeled. See the picture below to help you identify the polarity of the battery ends. Note the positive lead will have the positive side of the battery touching it and the negative lead will have the negative side of the battery touching it.

Step 3: Complete the Circuit

The metal binder clip will complete the circuit by touching the postive and negative sides of the batteries. The LED should light up.
The finished light can be thought of as a sandwich. Starting on the outside is the binder clip, then a layer of masking tape, followed by LED leads, then batteries, and finally the other side of the binder clip.
The arrangement allows you to stick the light on your clothes.

I noticed that clip sometimes did not land on the parts correctly and the circuit failed to complete. Moving the clip around a bit helps locate it in the right spot.

The next step shows and optional way to finish the light.

Step 4: Optional Arrangement

Instead of using the metal binder clip to complete the circuit, the two batteries can be brought together by folding the masking tape. The positive and negative ends need to be pressed together. The binder clip is still used. It presses the part together since the tape is not typical strong enough to hold the parts tight together.
With this option the layers are:
outside of clip
masking tape
one LED lead
one battery
second battery
second LED lead
masking tape
other side of clip

Note the batteries need to placed so a positive side presses against the other's negative side.