I am currently working on a project to classify and categorise sensors, to determine their capabilities.

As part of this project, I have got my hands on a tiny little sensor made by Gumstix, this particular model is a connex-400xm-bt which can run a pretty functional version of linux, and can run things like Apache, SSH, MySQL(?) and Java.

The main motherboard is circled in the attached picture, and is tiny, the specification on the site suggests that it weighs less than 2 teaspoons-full of water :) It has an intel XScale 400MHz Processor, which is probably more poweful than my first PC.

The other things in the picute are the serial/usb connector, WiFi and CF Connector.