MODS

First of all, here is the easiest way to add a lithium cell to your device. Adding a 3.7V lithium cell will increase your range.
Before:

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After:

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This is another style of Lithium battery that can be used as a power source. I have not tried this yet, but this flat lithium cell would save a lot of space. These flat cells are very easy to dent and damage, so be careful. Be careful with lithium batteries because if mishandled, they can lead to a violent chemical reaction. Never short them out, or overwork them.

Other Small Mods

-If your indicator LED is too bright, lightly sand it, or paint nail polish or White-Out over it.
-Make a 3x AAA battery souse for extended range
-add a switch to turn the EU codes on or off
-salvage a taller button so you can have the device in your pocket and feel where the button is
-Add more transistors or an n-channel MOSFET and more IR LEDs for increased range! There are instructables on how to do this.
-use 4 narrow beam IR LEDs for increased range
-use a high power star IR LED (now you're getting little too serious)

 

In my Arduino based TV-B-Gone, I used an n-channel MOSFET (D2061) to amplify the signal from one led to power 8 LEDs. See the page on Ardiuino Duemilanove based TV-B-Gone. For more information on what an arduino is, click here.
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