I have a ZigBee PIR motion sensor I purchased off eBay for under $20. It uses 2 AA batteries and I connected it through my Echo Plus (built in ZigBee hub). It shows under my devices as first motion sensor, second motion sensor, etc. I use them in routines, for example: I havea long covered front entryway leading to my front door. I mounted the motion sensor on the wall about 4' high at the entrance to this covered area. I wrote a routine that when it senses motion, it turns on the 2 smart can lights in theis area, then makes the announcement on my main Echo that that the front door sensor was just triggered. After a 5 minute wait, it turns off the porch lights. This works great to light this area at night for visitors as well as giving me a prealert that someone is at the door.