Last year, I took a look at some mostly low-cost passive infrared (PIR) motion sensor modules. Then recently, I became more aware of cheap microwave radar motion sensor modules. The popular version of ...

Most of us would probably expect to see a PIR sensor, but this light is motion sensing with microwaves. We have seen such units tested in the past, which links to a video [hclxing] also references.

Using motion detectors and an Arduino you can trigger lights, fans, or even an pneumatically controlled cleaver-wielding clown to help add your house to the “if you dare” list.