Very limited range with RCWL 0516 doppler motion detector

I have just got hold of an RCWL 0516 doppler motion detector and set it up in HA as a binary sensor using ESPHome and an ESP32. Everything works and the sensor will detect presence and I can switch a light. However, the sensor detects presence only over a very short range (less than 5cm)

Everything I read suggests the RCWL 0516 has a sensing range of 6-7M, even through walls but not mine! Has anyone else had this problem? Any ideas for a fix?

Do you have a wiring diagram? Your esphome code? Your logs.

Supply the RCWL-0516 with 28V on the Vin Pin and do forget the common ground

Here is the diagram:

and here is the ESPHome code:

Apologies if I haven’t supplied this in the best way. I am new here !

  name: mm-wave-test

  board: esp32dev
    type: arduino

# Enable logging

# Enable Home Assistant API
  password: "SECRET!"

  password: "SECRET!"

  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
    ssid: "Mm-Wave-Test Fallback Hotspot"
    password: "xxxxxxxxxxxx"

  fast_connect: true

# RCWL-0516 Microwave Radar Motion Sensor
  - platform: gpio
    pin: 4
    name: "ESP32 Motion Sensor"
    device_class: motion
type or paste code here


I have the same issue here.

First try was to replace a PIR sensor conected to ESP8266, and I realized that short range dectection (aprx 5cm).

I have two units here, so I tested the second directly conected to power supply and using oscilloscope to check output… so totally isolated from other electronics (there is a router and computers half meter away). But same behaviour.

Sensitivy resistor (R9) should be 220ohm, which seems to be correct.
Acording with the scheme I saw ( R1, which is inline with Vout, should be 100ohm, but in the board is 1k… but this shouldnt be the reason for the low detection range.

Faulty boards? Any suggestion will be more than welcome :slight_smile:

What voltage did you apply on the Vin pin of the RCWL-0516? Many people mistake the 3V3 pin as input but it is actually a output!

Cramp the voltage up (up to 28V are allowed in the datasheet for that board) - these sensor are known to perform poorly on 5V (specially when sharing the power source with the esp).

And as you adventures with your oscilloscope anyway get the Analog pin broken out and analyze it!

You can find the analog output on the IC (RCWL-9196) Pin 12:


The R-GN pad on the back is actually to modify the distance - but without any resistor soldered it should be around 7m, a 1M0hm should bring it down to 5m for example:


HI! Thanks for your answer! Very apreciated.

When I test the module isolated, I tried different voltages, from 5 to 12v, with same results.

I tested the analog out as your suggestion, unfortunately it doesnt give any additional value. Only reaction when movement ocurs really close to the module. If a capture of the oscilloscope is interesting for you, let me know and I will take some pictures.

Also checked the out of 3v3 (pin 2), and its ok (just to check if internal regulation might be broken).

I read about R-GN pads, but as you said, its to reduce the range from 7m to something smaller… Not our case at all :frowning:

probably that is the case then. I own a bunch of these and they typically have the “opposite” problem that they are “too” sensitive. Do you have the “newer” (improved) version with a ldo on the backside of the pcb or the older one (without)?


Do both of your units behave the same? Same batch?

Mine do not have any voltage regulator. I understood its inside the IC… My two boards are from the same batch, yes (in fact both were still together when they arrived and I had to split them), and both behave the same.

I have tested supplying 3v3 directly to pin 11 (just to check if the reason for the new board is a problem with the internal LDO) and didn’t help at all.

I will order a couple more from different supplier. Could you show a photo of the Upper side of the new version?

That’s definitely worth a try because they should behave differently (mine from various suppliers all do)… maybe you want to name/link the supplier you got the (probably) faulty boards from? Maybe @bluerover sourced them from the same seller :thinking:

Hi there

I sourced mine through Amazon. Interestingly, I have noticed that sometimes I get a response from the board from around 1m range? I haven’t changed anything and the response is inconsistent.

I bought them from random Aliexpress shop.

Just order some of those version 2 you showed. I will update as soon as I test them.

Thank for your time mate!

I just checked and they came from AZ Delivery. I am going to try increasing the supply voltage to around 20v. I read that performance can be inconsistent with only 5v.

Hi guys, I have the exact same problem. Correct detection but only 5cm range… Have someone found a workaround?


I had same problem but it was caused by inteferences for sure. I tried to change room and made a minimal circuit only with power supply, sensor and at the output one led + resistor and range increased several meters.

Hi All,

I had the same issue. I have found one solution for my problem. Would like to share with you all.

My setup was using an ESP8266 based Wemos D1 mini board and had RCWL 0516 interfaced to it. I only got about 2 cm range. I tried searching the internet and did not get any proper solution. I learnt that the module is very sensitive to electromagnetic interference. So I got a doubt and tried the following solution. It worked very well.

I ensured that when the motion is being detected the WIFI from the esp8266 is in the OFF mode. This ensured that there was no interference due to the ESP8266 wifi. Magically I could now get the range for 6 to 7 meters. A great improvement.

So if you are using any wifi based board - ensure that it is turned off for the detection time. Once motion is detected you can connect to the internet if required and pass on the message. But remember to put off the wifi at the end so that detection resumes.

Hope this is useful.

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Do you have any example to share of this? Hopefully in ESPHome

The manufacturing of these boards is just garbage. I’ve used many of these boards and been following threads like this for the rcwl for years. if you read these threads and reviews online, there’s a common theme. These boards are often DOA and there are a dozen user submitted “fixes” that sometimes work but often don’t work. Youll see fixes like the one above and turning off the wifi makes the least sense IMO as now the board is useless for anythibg else as you wont be able to communicate with it. If you have a lot of wifi interference in your home which is common these days, it wont matter if you disable it or not. The only reason these boards are still around is because when you have a batch with some that work, these things work really well! You can put them inside non-metal enclosures and they detect motion and they even detect motion through “some” doors and walls. Instead of turning off the wifi. The best thing I’ve found to work is to put then in places far away from routers or access points and give yourself as much distance between the esp and the sensor by using longer wires. IF the boards are even working, this is usually all you need to do. You have to keep in mind that these boards aren’t for every location and in most cases they work best used as a part of a motion detection pair with something like a PIR that can have false positives and not as the sole sensor for detecting motion.

I just bought some more of these on amazon. I almost always get good quality products from the Hiletgo store and 3 of the 5 sensors I have tried so far, they all work great. The ones I have tested are 4" from the esp8266 board and they are detecting motion on the opposite side of the room i’m in, roughly 12’. The Hi-Link ld2410 mm wave sensors are expensive compared the the rcwl and PIR sensors but they are highly configurable and work pretty much the same way as the rcwl sensors and they work really well.