tail -f ZS64.log

Measuring temperature in a PC should be easy: after all, most mainboards have extensive monitoring capabilities for temperature and voltage levels built-in. Unfortunately, very few of these facilities are documented properly, and software support is lacking. Instead of trying to navigate the maze that is lm-sensors (which isn’t even available for FreeBSD), I decided to look for some USB-based solution.

There’s a reasonably cheap chinese USB thermometer called TEMPer. I got mine from Brando for 12 Euros. It’s a USB-to-serial chip from WinChipHead. It’s DTR, RTS, and CTS lines are used to connect a LM75 I²C temperature sensor. To talk to the LM75, you need some bit-banging driver.

I’ve put together a command line utility for the TEMPer that can program the built-in thermostat (TEMPer has a LED connected to that output) and print out temperature measurement data. It does it’s job, and might serve as an example on how to do I²C over a simple interface.

We were in need of replacement hardware for our two Shuttle K45 we’re using as servers, since one of them developed a case of capacitor plague, and the Asus Pundit4 P5G41 turns out to be a nice choice. It’s compact, features a LGA 775 socket, two DDR2 sockets, space for one 3.5″ and one 5.25″ drive (SATA only), and even has a serial port built right into the case (we’re big fans of serial consoles).

This model seems to be relatively new (introduced apparently in the fall of ’09), and I couldn’t find any pics of the innards. I’ve added a couple of interior photos to our wiki. Enjoy!