Microwave Radar

tmpBA87As soon as one mentions “microwave radar” I’ll bet you’re thinking “expensive” – well how does under 2 quid sound…


These little devils are movement detectors, bought from Ali Express on a whim and they use the PCB as the antenna (3Ghz) – 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.

Updated April 2017 – see also https://tech.scargill.net/microwave-for-the-weekend/

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.

What I DID find when testing this and a later model (see above) is sensitivity to power supply – it is probably no good sticking it on the same supply as an ESP8266, the noise spikes will make the board unreliable. My solution is a 10r resistor in series with the 5v supply – and a 330u 6v cap (from the microwave board end of that resistor) – to ground – works a TREAT.

Both sensors work well, let’s have your thoughts  (no theories about getting cancer from radiation please).


67 thoughts on “Microwave Radar

  1. Is it possible to somehow get out of the module both the strength and the phase of the reflected microwaves?

  2. I’ve been experimenting to used it as presence detector in combination with an ESP-01 in the same housing. Although I tried to shield it from each other, the WiFi signal was influencing the radar signal and false detection’s where made.



    1. Interesting – I would not have thought of that! Thanks for the feedback Martin. Let us know your final solution.

  3. Yeah, there is amost no data to be found on the net about the XYZ-WB-D1, unfortunately. I seems to be a decendant of the original design, using just one single board (which probably reduces manufacturing complexity). Unfortunately it lacks the convenient multiple pads of the WB-DC, featuring only one single pair of pads labeled “PT” (photo transistor??).
    Got it yesterday, along with some other tiny module which is a round sandwich design with a diameter of only about 1 inch, named “XYZ-WB-12” which features undocumented pad pairs named “PT”, “Time” and “R15” (guess: sensivity).

    1. Is it possible to detect “Relative Motion”? I am trying to detect the positions of the objects in the room. If I make it directional by using alufoil, and put it on a servo or a stepper motor and scan the room; will I be able to get positive response at some angles? No response at all, or response at all angles?

      1. So, I bought a few of these units, and tested myself. Yes you can direct the beam by masking most of the antenna with a piece of alufoil leaving a small gap. Yes, I get response at SOME angles, not all, not none, but they do not seem to be consistent. I placed the unit on a stepper motor and scanned 275 degrees by 7.5 degrees increments. I did both digitalRead and analogRead on Arduino. I plotted analog echoes on XY. Broadly speaking, some echoes are overlapping but mostly they are inconsistent. Hard to say that we get echoes for the same object consistently.

  4. Has anybody confirmed that the modules Peter linked to do in fact work at 3.3V? I have ordered something similar (XYC-WB-D1 modules) and they only work at 5V, which is an inconvenience…

    1. I’ve got XYC-WB-D1 modules as well, and they seem to work at 3.3V. I’m not sure which resistors to modify to change the behaviour though.

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