| Keyboard Light Bar for the Laptop |
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 Laptop with red screen filter and light bar |  Help for my old eyes! |
| The red acrylic filter did just fine for making my laptop screen "night friendly", but I had a tough time seeing the keyboard. This bar slips onto the top of the red filter, and provides adjustable lighting for the keyboard and the area right around the laptop. An internal voltage regulator lets me power the light bar with anything from 4-30 Volts. It can run for days on a 4 x AA battery pack, but it usually gets its power from my Power Box supply, which runs almost everything I use. Here are some of the details: |
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| The outside of the light bar is a piece of aluminum channel. The inside was made by routing a reflector shape and a wiring groove into a piece of wood. The reflector surface is chrome tape (auto parts store). | |
 Ready to slip onto the filter. Power jack is on the left end, dimmer knob on the right. Seven red LEDs provide a uniform light field. |  Wood center with wiring channel and LED reflector |
 Closeup of the dimmer circuit |  Power jack and voltage regulator |
| The voltage regulator is a tried-and-true LM317 (technology almost as old as I am). | |