Sniffing the SMBus
There's plenty of ways to add a temperature display to a desktop computer. But capturing temperature readings from the system management bus (SMBus) isn't among the widely used techniques. As the SMBus is very similar to I2C in its nature, technically it shouldn't be too complicated to monitor (and decode) the data exchange on the board. Unfortunately, there's a bunch of challenges included here, as the hardware I2C on many microcontroller boards will only capture traffic directed to a single slave address. Here's my workaround, showing how to use a Teensy 2.0 to capture the data.