The Staniot PR200 wireless motion detector awaits you on sale on AliExpress, at 2.26 euros instead of 6.76 euros. Equipped with 2 batteries, this wireless detector communicates with the “brain” of the system on the 433 MHz frequency band, up to 10 meters away.
It uses a PIR motion sensor calibrated so as not to react to the comings and goings of your pets. The alarm trigger time can be set to 5 seconds or 5 minutes.