RFID tracking system

[Nicholas] built an active tracking system using RFID tags. The system’s tags operate in the 2.4 GHz band and are used to track either people or assets. The readers are on a mesh network and can triangulate the location of any tag for display on a map. His system is even set up to show the travel history of each tag. [Nicholas] shared every detail in his writeup including some background about available hardware options and how he made his final decisions on what devices to use for the job. His conglomeration of software that ties the whole project together is also available for download.

WiFi spectrum analyzer

ez430 (Custom)

[Tim] noticed a 2.4Ghz WiFi spectrum analyzer on thinkgeek a while ago and got curious.  He knew that the spectrum analyzers with which he was familiar were giant expensive units, so he got curious what this little dongle was. It turns out, it really wasn’t much at all. Just a simple wireless receiver. He decided that rather than spending the $399 for one, he would toss one together using an Xbee. His total cost ended up at roughly $50 for basically the same unit. While he doesn’t give a schematic, you can download his source code on the site.