There are some interesting doppler radar modules available for cheap at the usual suspects (Ebay, Aliexpress, ...). However, sadly there is very little information out there on how they work and how to process their output signals. In this video I explain the inner workings of a HB100 and you can use your PC's sound card to gain some interesting measurement.
The software I've used to analyze the output signal is "Visual Analyser": [ Ссылка ]
Another excellent video about a very similar module : [ Ссылка ]
