Installing a fan on my Printrbot improved print quality. However it also made it difficult to see the print progress. It's just too shadowy! So I edited PaulRac's fan mount and made it into an LED mount. It works great! Now I can see!
I'm using 12V LED strip. It only consumes 50ma, so I just wired it to the same PSU that powers the PrintrBot.
BTW, this particular LED strip is so bright that without the blue tape, the reflection on the glass is unbearably bright. So, I installed a switch.
Make sure you solder everything and securely route your wires. We're installing the LED in a constantly moving platform. Any short would likely interrupt the print or worse.