Speaking of radars... Did you know a useful radar is now just 34 US cents?[1] And that chip? Not even designed for this application - it is a PIR sensor

Speaking of radars... Did you know a useful radar is now just 34 US cents?[1] And that chip? Not even designed for this application - it is a PIR sensor chip repurposed. The core of the radar is just a single multi-Ghz transistor (in the middle of the left half of the PCB), and a super clever feedback circuit made out of fancy shapes of copper traces that probably took someone years to design and perfect. [1]: https://www.aliexpress.com/item/1005006240906322.html https://www.aliexpress.com/item/1005006240906322.html