These little devils are movement detectors from Ali Express on a whim and they use the PCB as the antenna – hence the ridiculously low price. So just a quick one – I ordered 2 and they arrived the other day – I’ve hooked them up to 5v (they work from 3v3 to 20vDC) and use less than 3ma. 3 pin connector gives a positive output on movement – and the output stays high for around 30 seconds.
On the back there is a pair of connection points (soldering iron needed) and if you put a 10k resistor across them (I found this out by trial and error as there is very little info on these units – at least in English) the pulse goes down to around a second. VERY sensitive and although I’ve only done the briefest of tests I can confirm they can detect hand movement through 0.5” of chipboard !!
According to the blurb they pick up movement 360 degrees and have a detection of 6-9 metres. Applications include security, intelligent lighting, toys etc.
That’s as far as I got – no doubt someone will come up with some great ideas for these – let’s have your thoughts (no theories about getting cancer from radiation please).