Thermographer
(above, the first step was to 'clone' an off-the-shelf non-contact IR thermometer)
The DIY thermographer is a camera which creates an image of what temperature things are -- a 'heat' camera. We're making a 'scanning thermal imager' which means we just use a temperature sensor and sweep it back and forth over a scene, recording the temperature variation to build up an image that looks like this:
There are two main parts to the project: the camera itself (currently made of Legos and an Arduino, and the website, thermographer.publiclaboratory.org, which helps you create an image from your recorded temperatures. Both are under development and we don't yet have a demo to show you. Check back soon!