[Blacklight99] made this cool tool. It is a tester for those radar detectors that people keep in their cars. Though this seems like it would rarely be a tool we would need, it’s an interesting project. Some speed guns that the police use have a “stealth” mode that makes them invisible to some detectors. This tool can tell you if your detector is vulnerable to this. While this really is just a complicated flashing LED, he notes that it could be taken further to be made into a detector that is programmable and not vulnerable to any of the stealth modes.