discussion / Camera Traps  / 23 February 2022

Experience with Microwave Motion Sensors!

Hi all, I'm looking for anyone who has any experience in using Microwave Sensors, such as the rcwl-0516, to detect the motion of birds/mammals for triggering camera traps.

I'm currently experimenting with this myself, so any experience people have or advice would be greatly appreciated!


Hi Tom,

I very much like your idea of external triggers for regular camera traps, and I believe Akiba @Freaklabs has been doing some work in this regard.  I've had a fiddle with radar modules but for a different purpose, and I think for detecting birds and small ground mammals it is one of several options.  For instance there are PIR units such as AM312 that draw very little quiescent current, or you can use a rugged reed switch which draws none.  I have the beginnings of a vibration sensor for the same purpose.

As far as I can figure, the rub is in triggering a camera trap that doesn't already come with an external trigger port (which is most of them).  It's not very hard to hack a camera trap to accept an external trigger signal (while retaining the original functionality), but it is a pain.  I've tried discretely triggering the camera's PIR, but this is quite a bit more complicated than it might first appear.


Hey thanks for the response!  I'm actually building my own camera trap using a Raspberry Pi 4, sorr yI didn't put more detail in my original post.

It's got some machine learning code running on it tha tries to detect a bird in the image in takes, then attempts to classify what bird is in the photo.  Hacking into a pre-existing camera trap isn't what I'm looking for really.  I've used PIR sensors, but they're a bit sketchy at times and can be overly sensitive.  I'd also like something that works through a clear plastic screen due to weatherproofing conerns.

Hi Tom @TomRS 

I have zero experience with microwave, so I am absolutely no help, (this a recurring theme of my life), but I just ordered one as I am trying to build a 'better' motion sensor for triggering SLRs. The PIR-based one I've built is pretty temperamental. This is the model I bought: https://littlebirdelectronics.com.au/products/gravity-arduino-digital-microwave-sensor-motion-detection Is that the sort of thing you are using? Keen to see how you go and other replies as they come in.

There's also a fancy radar model (https://littlebirdelectronics.com.au/products/24ghz-microwave-radar-sensor) from the same supplier. Is this similar to what you've been looking at @htarold ?




Hey @Rob+Appleby 

I'm using one of these:  https://hobbycomponents.com/sensors/899-rcwl-0516-microwave-radar-motion-detector-

The ones you listed are quite fancy in comparison!  I'm making good progress with it, it was easy to hook up, but I haven't tried to adjust sensing range by soldering resistors in etc.  In terms of detecting motion it's great, I need to tweak my code though in order to delay photo capture by a few seconds to let birds/mammals come into view properly.  This might be where I need to reduce the sensitivity of the board with resistors!