This code project is centered around the Dallas Semiconductor 'MicroLAN' (tm) series of parts. These include an inexpensive ($5) temperature probe as well as single and double pole switches. They are all tied together via a "1 wire bus" which is actually a 2/3 wire bus: data, ground, and optional power. Literally hundreds of sensors may be placed on the same bus. I currently have 9 temperature probes spread around the house from attic thru basement to the yard.
Each channel provides 3 thumbwheels for setting:
When a under/over temperature is reached the LCD changes from green to yellow or red and a user provided callback is invoked. The code for the daemon is in here while the code for the client is in this package
Artwork for the mlDaemon serial port controller in PCBCAD format. This is derived from an article in Circuit Cellar Inc. (tm).
The original computer hardware monitor version is still around. It is anticipated that this might use a HALT procedure, followed by a powerdown of the affected hardware.