A couple of weeks ago, I had the idea to make an LED flashlight that would sit on top of a 9-volt battery clip, but would run on one of those 2 x AA holders with the 9V clip attachment. Well, I made it and documented the process and was very happy with the finished product. It can be used for finding your way in the dark, looking for that box of batteries you know you left in your closet, or better yet, (by adding a toggle switch) it can be used on your bike or scooter when riding home at night. The pictures of the light with a 9V battery are just for ease of recognition, I guess.

Step 1: Stuff You'll Need

For some people, getting the materials for this light will be as easy as looking around your desk. For others, most all the parts can be easily obtained at RadioShack or somewhere similar. The things you'll need are:

- A 9-volt battery clip like the one shown
- A tactile switch*
- A non-diffused LED in the color of your choice
- A resistor to fit the requirements of your LED**
- A little holder for your LED***
- A battery****

- Soldering iron w/ solder
- Hot glue gun w/ glue

*You can salvage these out of tons of electronics. Listen for the buttons that make that characteristic 'click' sound when you press them
**Resistance equals Voltage divided by Amperage (R=v / i)
***Optional. If you want one, you can buy one, or you can make one, or you can get one out of disposable cameras as the holder for the neon lamp (that's what I did)
****A 9-volt works okay, but it may overpower your LED. You may want to try those 2 x AA holders with the 9-volt style clip on top from Radioshack that I talked about earlier.

Step 2: Gluing and Soldering

You can glue first then solder, of solder as you go. I prefer the second method.

1. Glue down your switch as shown. If your switch has 4 tabs, you can probably break off the ones on one side.
2. Glue down the resistor, bend the wires and solder one of the leads to the switch.
3. If you have an LED holder, go ahead and glue it down. If you don't, then glue your LED where the holder would be.
4. Put the LED in the holder and solder a lead the the resistor, making note of the polarity
5. Clip the wires from the 9-volt clip to length and solder one to the switch and one directly to the LED

Great! You're done building it. Now let's test it...

Step 3: Testing

Press the switch. If all is well, the LED will light up. If not, make sure the polarity is correct throughout and that your battery still has a charge in it. After things are fixed, try it again. It should light up brightly. Some modifications that could be made to optimize this little light for biking are changing the switch from a momentary tactile to a toggle or slide. You could also swap out the LED for a flashing one to become more noticeable. Make sure to comment!