I decided to build EFFICIENT power supply for my EEEPC 900. The laptop takes about 60mA of current while powered down and about 70mA while in suspend mode. I must mention that i removed the battery from the laptop to avoid it being charged from car battery and drain it empty.

Car battery has voltage of 10 to 14 volts probably and the laptop uses 12V input voltage. Normal switchers use transformer to generate this sort of voltage. Transformers are not efficient though and i don’t want to drain the car battery to generate heat.

So I came up with this device from National Semiconductor. LM5118. With my USB TV and active antenna connected, laptop took less than 2 Amps at 12V … P = U*I = 12*2 = 24Watt

lm5118

Asus EEEPC 900 for my car

This is what i am working on.. The device that enables you to change your effect processor’s patch remotely – from a button push on your guitar’s neck or something…

Ok.. at the moment I can say that the damn device is changing the patches from ‘MIDI in’. I will update this post when i make it work over the wireless.

The controller connected to Rocktron VooDu Valve MIDI in port.

Eagle CAD files for FT232 USB to Serial converter:

usbser_schematics
usbser_board
FT232 datasheet