[Jeroen Domburg], one of our favorite hackers, has posted how to replace a cold cathode based backlight with white LEDs. He had recently purchased an HP Jornada 680 on eBay and the backlight was looking very pinkish. The Jornada has a QWERTY keyboard, CF slot, PCMCIA slot and can run Linux. Sounds like a pretty decent mini-terminal (now that we posted it you won’t be able to find one cheap though). In the space where the backlight was he was able to place 14 white LEDs. To get the 40V necessary to drive the series he built a boost-converter using an ATTiny13. The new backlight is just as bright and uses a 1/3 less power than the original. Half the Jornada’s power was being used by the original backlight, so this mod should give a decent increase in battery life as well.
