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How to build a cheap LED reading light for your Kindle or Sony Reader

So last night, while I was watching Heroes, I built this little guy:
Kindle LED light (prototype B)
This is just the first prototype of a better-designed LED light for the Kindle that I have in mind (but some of the parts are still on order). However, this is dead simple to make, and I happened to have all the parts lying around (after the LED lights I’d ordered arrived yesterday).

Parts needed:

  1. One Ultra-Bright White 5mm LED—Cost $0.98 each; I bought 5 and they arrived yesterday.
  2. A 3V CR123A camera battery—These can be had for as cheap as $5 for two. They also come in rechargeable versions for more money, which I would have used, but I had some already lying around. What’s good about these batteries for this no frills LED hack is that they stand one-and-a-quarter inch tall, weigh practically nothing, and are thick little batteries that act as both battery and stand for the LED light.
  3. Aluminum foil—You could use wires if you want to get fancy, but at 3V of current, some mangled, twisted and shaped aluminum foil works fine, and you can even bend it nicely so it acts as a nice switch.
  4. Tape—I’d prefer electrical tape, but I couldn’t find any yesterday and it’s only 3V so I just used regular Scotch tape.
  5. A large rubberband.

Once you have all these parts, you take the positive contact from the LED (it should be the slightly longer of the two contacts) and wrap it around the top bump (what is this part of the battery called?) of the battery, then bend the LED slightly downward to sort of lock it in place. It should fit snugly before you add any tape.
Kindle LED Prototype B construction
As you can see, the negative contact from the LED shoots up into the air at about a 45 degree angle. This is perfect. Put a piece of tape over the top of the battery.
Kindle LED Prototype B construction
Then take your aluminum foil and fold it into a thick little strip about 2-inches tall, roll up the very end and tape that firmly to the bottom of the battery. You’ll want to shape this into a little arm so that it can connect with the negative contact on the LED to turn on the light.
Kindle LED Prototype B construction

Now the basics of the light itself are done. Here’s a picture of it in the off position:
Kindle LED Prototype B construction
And here’s another of it in the on position:
Kindle LED Prototype B construction

Then you just take your rubber band and place it across the top of your Kindle (being careful not to have it pushing the volume controls on the right side of the device) and carefully slide the light into place held firmly between the Kindle and the rubber band.
Kindle LED Prototype B construction

This should work with the Kindle, the Kindle 2, Sony’s Reader, or really any ebook reader of similar form factor. As you can see from the picture above, it’s not the most nicely polished LED light and it lacks a uniform dispersal of light. However, it does work and it does so without getting in the way of the ways I normally hold my Kindle. It also avoids adding any noticeable weight to the device.

Next steps: This was only Prototype B for this LED light; I used it last night while reading in bed, and it got the job done (and for less than $6!), but I definitely want to improve upon it. I plan on making a better one when the parts I ordered arrive. I intend to use a smaller 3V battery like the ones used in LED throwies, build an actual arm for the light so that it isn’t dependent upon the battery for a stand (and so that it is adjustable), and add some sort of diffuser and perhaps a mirrored surface along one side of the LED, so that the light is distributed more evenly across the page. Stay tuned.

Comments on this entry are closed.

  • Parts Express 4/28/2009, 7:43 am

    Nice job on the hack. I've made the LED throwies before (actually have a few on my desk) and they are pretty sweet, especially if you make one using a color changing LED.