Project
Making a simple USB desk light or light strip
Category
Published
Mar 11 2011 by Electro
Share
Quick jump
Many people are always wanting to know how to make a desk light powered from your computer. The answer is USB power with 5.0-5.5 volts available all the time it's the obvious choice.

The great thing about making a light using USB power is the ability to wire in LED's directly in pairs without a need for a resistor at all.

This project will demonstrate the most simple method of creating a group of LED's powered by USB.For this project you will need:

- LED's , I used daylight LED's which run on 2.2v to 3.1V with no issue.

- Soldering iron with solder (tin/lead will do)

- Wiring.

- A mounting surface (Even an old DVD / CD can be used!)


I wanted a tray of lights to be mounted under a shelf as part of an effect, because of this the bulbs are quite evenly spaced out, for a brighter lamp just move them closer together. If your using an old DVD/CD then simply drill paired holes for the LED legs to go through.
/media/Electro/USB Light 1
I used L bracket length of aluminium shaped into a ] shape.
/media/Electro/USB Light 2
Using a hot-glue gun I fixed the pieces into place.
/media/Electro/USB Light 3
The LED's pair off with the longest leg as positive (notice the red tape). First I bent the positive leg too a rough bend, then did the same on another LED but on the negative leg. This provides a pair of LEDs that can be wired up and powered together.
/media/Electro/USB Light 4
To create the entire circuit I used 1 piece of electrical wire with slits cut into the insulation to provide a bare patch of wire, then soldered the legs into the patch, 1 in the positive line the other in the negative line.

You can however wire each group direct too the main power connection, because 2 LEDs uses all the available current within limits means you need no resistors in line at all.
/media/Electro/USB Light 5
The main connection for power simply requires chopping off the end on a old USB lead, inside you will find 4 cables (usually red, black, white and green). It's as simple as it looks with red as positive and black as negative.
/media/Electro/USB Light 6
You can see the effect from well spaced LEDs is a good glow but not in your face silly bright :)
/media/Electro/USB Light 7
Other projects you might like