Home > Hardware > Tiny Microwave Radar Module Detects Movements Up to 9 Meters Away for $2

Tiny Microwave Radar Module Detects Movements Up to 9 Meters Away for $2

PIR sensors are used to detect motion for example to turn on or off a light bulb when motion is detection. One such sensor is HC-SR501 motion detector, which costs around $1, and is tiny (32 x 24 mm), but not quite thin due to the design that needs to capture infrared light, with an height of around 2 centimeters. If you’d like something almost as cheap, just as small, but much thinner, microwave radar modules could be a good alternative.

XYC Microwave Radar Module vs HC-SR05 PIR Sensor

XYC-WB-DC Microwave Radar Module vs HC-SR501 PIR Sensor

XYC-WB-DC is one of those modules with the following specs:

  • Operating Frequency – 5.8 GHz
  • Detection angle – 360°
  • Detection range – 6-9 meters
  • Working Voltage – 3.3-20VDC;
  • Standby current –  <3mA;
  • Transmit power – <2mW;
  • Dimensions – 32 x 23 mm
  • Operating temperature range – -20 ~ +80 Centigrade;

Potential advantages over PIR sensors include wider detection angle, and lower power consumption, HC-SR501 datasheet reports respectively 120 degrees detection, and 65 mA “power consumption” @ 5V. The range is about the same for both PIR and Microwave radar modules, but the microwave module will also work through walls (which may be an advantage or an inconvenient), and the signal can be blocked by metal.

The module will output high signal (3.3V) when motion is detected, and the detection delay can be adjusted from 1 second to hundreds of second (two minutes max) by adjusting R6 resistor on the board as explained on this Taobao page (Chinese). By default there’s no resistor and the delay is 30 seconds, and you can adjust the delay by using 1K to 250K resistor.

Microwave_Radar_ModuleI’m not sure what the other resistor (10K – 100K) is used for (maybe max distance), which brings me to the downside that there’s absolutely no info in English. However, I found this module on Pete Scargill blog, who tried it, and could confirm motion is properly detected.

Other applications for such modules include security, body sensors toys, industrial automation and control, auto-sensing electrical equipment, and battery-powered automatic control.

XYC-WB-DC microwave radar can be purchased for about $2 to $2.5 on Aliexpress, eBay, ICSstation, etc…

  1. onebir
    April 4th, 2016 at 12:04 | #1

    What happens if you take the dome off a PIR sensor? (Maybe they just become much more directional?)

  2. Jesu
    April 4th, 2016 at 12:26 | #2

    I hope that the bats do not cause any problems. Useful little creatures. In the evenings, diligently collected insects.

  3. Sander
    April 4th, 2016 at 12:48 | #3

    Cool. I ordered two.

  4. Jon Smirl
    April 4th, 2016 at 18:42 | #4

    No dome on PIR makes them more directional. The dome is a multifaceted lens.

    These operate in the same band as 5Ghz wifi. Do you really want to ruin your 5ghz wifi? Wifi channels over 149 are in the same band.

    • sykophantes
      July 14th, 2016 at 05:44 | #5

      5 GHz wifi operates at 5.15-5.7250 GHz, This is supposed to operate at 5.8GHz and would not overlap, supposedly.

  5. DX
    April 4th, 2016 at 19:24 | #6

    @Jon Smirl
    That’s the inherent problem of RF based solutions: if you use open band then ether it will be used, or is already used, by something else.

  6. monopole
    April 4th, 2016 at 19:59 | #7

    @Jon Smirl
    This is a common misconception.
    Taking the dome off makes the PIR useless.
    http://www.glolab.com/pirparts/infrared.html
    Basically, the sensor in a PIR detects long wave IR, which is emitted by human beings, and everything else, including the detector and the sensor. As a result the signal from an uncovered detector is very weakly varying. The clever trick that makes the PIR work is that the array of Fresnel lenses modulates a hot spot as it moves across the field of view and an analog circuit picks up this modulation. As a result the PIR only detects the motion of a hot object as it moves. This may be readily verified by standing still in front of a PIR. In the same fashion, removing the dome also disables the sensor, but if you place a spinning disk with slits in it in front it will work again.

  7. smob
    April 4th, 2016 at 21:27 | #8

    Is there anything like this that outputs more data from the sensor than just a binary ‘movement: yes/no’ signal?

  8. WesR
    April 4th, 2016 at 21:58 | #9

    Translating the specs to English should be a non-issue. Surely, there is a geeksite that does this?

  9. onebir
    April 5th, 2016 at 00:55 | #10

    @monopole
    Then couldn’t a flat fresnel lens work (again with increased directionality)?

  10. iamfrankenstein
    April 5th, 2016 at 01:14 | #11

    The google translate app does appear to translate the picture quiet well. If you have the google translate app you can just make a picture of the image on your screen and let him translate it.

  11. treblig
    April 9th, 2016 at 19:50 | #12

    The other resistor is for sensitivity adjustment.
    It is 20K by default and sensitivity decreases as resistor value goes up. Resistor range is 10K to 100K.

  12. Wrrr
    July 12th, 2016 at 18:40 | #13

    @Jesu
    Bats use soundwaves, we are talking radiowaves here.

  13. Joe Desbonnet
    December 21st, 2016 at 06:40 | #14

    Quoting from the article: ” HC-SR501 datasheet reports… 65 mA power consumption”. No, it’s 65µA (micro amps). PIR is definitely more power efficient.

  14. December 21st, 2016 at 09:04 | #15

    @Joe Desbonnet
    The HC-SR501 datasheet linked in the post reads:

    ◦ Voltage: 5V – 20V
    ◦ Power Consumption: 65mA
    ◦ TTL output: 3.3V, 0V

    and further down:

    1 working voltage range :DC 4.5-20V
    2 Quiescent Current :50uA

  15. AJ
    April 7th, 2017 at 22:42 | #16

    Just tested one of these devices. 5V 1.11mA (both measured as current, as well as voltage over a resistor). Current drops to 1.09mA when nothing is detected. Even then, PIR is much more energy efficient. When R6 is removed, ON time after detection is about 10s. R9_1 SMD marking is 123, R6 marking is 222.
    As PIR compares the two or four quadrants of its sensitive area, the lens is essential. No lens, no relative change, no detection.

  16. Graham Toal
    April 15th, 2017 at 09:44 | #17

    I just got a XYC-WB-D1 ( http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemVersion&item=112040243727 ) and connected vcc to Raspberry Pi pin +5V (phys 2) and gnd to gnd (phys 6) and out to GPIO4 (phys 7) – I’ve used the same hookup to read PIR sensors frequently – but the radar sensor always returns ‘1’ when reading the pin regardless of whether there is motion or not. Any ideas why?

  17. April 15th, 2017 at 09:53 | #18

    @Graham Toal
    Two potential issues based on:

    The module will output high signal (3.3V) when motion is detected, and the detection delay can be adjusted from 1 second to hundreds of second (two minutes max) by adjusting R6 resistor on the board as explained on this Taobao page (Chinese). By default there’s no resistor and the delay is 30 seconds, and you can adjust the delay by using 1K to 250K resistor.

    1. You may have to convert the 3.3V to 5V for Raspberry Pi. Connect an oscilloscope, or a multimeter to check the voltage
    2. Delay which can be up to two minutes depending on how your board is configured.

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