I recently picked up a couple of microwave motion sensor radar modules. You have seen (and perhaps tried) it before. This post is about the HFS-DC06 (DC5V/5.8GHz) Microwave Radar Sensor Switch Module!

Radar, at its simplest, involves sending out pulses of radiation that reflect off an object. The reflected signal is detected, and the time of flight is measured. The time of flight is then translated ...