LED Camera Light

This is project is originally from ProdMod and I built my version of one in about an hour. I had been looking for a way to put a camera light on my digital camera, especially for video, and this project fits the bill perfectly. All this camera light consists of is a modified 4-AAA battery case (with built-in switch) which has a 3/4" long 1/4" cap screw passing through it and 3 white LEDs wired to the batteries. To use it you simply thread the screw into the tripod mount on your camera and turn it on.

I used a different parts source than the original article, getting both the white LEDs and AAA battery case from Mouser Electronics. The cap screw can be purchased as a pack of 2 from Home Depot for $0.88. Other than that my camera light went together the same as the original article, with the exception that I used a 15 Ohm resistor instead of a 10 Ohm to protect the LEDs. I chose this in order to add the flexibility of using regular alkaline batteries or rechargeable batteries. Since alkaline batteries produce 1.5 Volts typically, three alkalines produce 4.5 Volts. Rechargeable nickel-metal-hydride batteries produce 1.2 Volts typically, so three batteries produce 3.6 Volts. This voltage differential means the current limiting needed to keep each LED's current draw under 2o mA is different if using alkalines or NiMH batteries. For the LEDs I chose from Mouser, the 15 Ohm resistor used with alkalines produces a current of 63 mA or 21 mA per LED. If using NiMH batteries this would amount to approx 17 mA per LED. Therefore, the 15 Ohm resistor is a good compromise that allows me to not worry about battery type.

USB Device Charger

This was a nice, simple project that is also very useful. Called the Minty Boost, as soon as I first read about this device I wanted to build one. Basically it transforms the 3 Volts from 2-AA batteries into 5 Volts and has a USB connector to attach the device you wish to charge (IPod, Sansa, cell phone, etc.); the bonus is that it all fits inside a Altoids Gum tin. You can build this from scratch, but some of the parts are somewhat uncommon and the printed circuit board is made to fit inside the tin so I just bought the kit (full kits are $19.50, PCBs are $5). It is a very simple kit to build and takes only about 30 minutes to complete. Then you just stick it in an Altoids Gum tin and you're done. Now I can charge my Sandisk Sansa's battery even if I don't have a computer or an outlet around.