Hi there, Kim from Auckland here (Originally).



Your fellow New Zealanders have the 

project in which they use low cost thermal cameras and ML models to detect small mammals. Being thermal it meets both your requirements. I would expect  that you meay be able to find some common ground with those chaps for this.



Althought, as that is also New Zealand based I would expect you to likely already know about them.

Cheers, Kim Hendrikse

Nathaniel Rindlaub with the nature conservancy give a talk a while back about their pretty sophisticated rat monitoring system on Santa Cruz island.

They used stuff from https://www.buckeyecameras.com/ 

Not sure what the cameras PIR capabilities are though. They were using AI image recognition.

Hope that helps!

Hi @MaddievdW have you considered using a 'tunnel' to help, well, funnel, small critters into a space with a camera that makes it a bit easier for detections? A few years back, we made a PVC pipe tunnel with a protected food lure that seemed to work well with even cheapy trail cameras (and in fact, we ended up having to block some of the IR illumination using a few layers of athletic tape over the LED array). Here's a rather blurry image of a bandicoot we got:

And another of an antechinus:

We weren't that concerned with image quality, as we were actually testing an RFID logger in the tunnel also, and simply wanted to know if we got critters with no tags and what species (if possible). So one thing I'd definitely consider if you go down this path is focal length of the camera. Here's a previous discussion on a similar idea: 

I guess you could always 'calibrate' it to a certain extent by just using a longer section of pipe. Here's what our set up looked like, but again, we had the RFID logger, so a camera-only version would be a bit simpler - the camera and battery was in the screw top section on the left-hand-side of the tunnel image and each entrance had RFID antennas linked backed to a logger in the same compartment as the camera:

All the best for your research,

Rob

Addressing each of the questions/issues posed: 

Triggering Camera:   

If you are getting triggers, but empty frames, during known visits by these lickety-split animals, the issue is the trigger speed.  Looking at the Browning selection guide, for example, https://browningtrailcameras.zendesk.com/hc/en-us/article_attachments/12697703673243

I see that the Elite-HP5 models have a 100 ms advertised min trigger speed, which is slightly (50 ms) than the Dark Ops Pro DCL.  This is equivalent to 2 earlier frames (at 60 FPS video), which could be significant with fast moving targets.  

I have found, BTW, counterintuitively, that for Browning SpecOps and ReconForce models (Elite-HP5) that camera gets to first frame sooner when taking videos vs. when taking stills.  I don’t understand this completely, but it’s a thing.  

If you are not getting any triggers, then the PIR sensor is somehow missing the target.  Make sure you understand the “detection zones” supported by your camera.  These are not published, but can be determined with some patience and readily available “equipment” – see my post on “Trail Camera Detection Zones” at https://winterberrywildlife.ouroneacrefarm.com/2022/08/01/deep-tech-trail-camera-detection-zones/

Putting more than one camera at a site may also increase the probability that at least one triggers (and may improve lighting, see below)

If you’re consistently missing triggers, you may have to consider a non-PIR sensor.  Unfortunately, this removes you from the domain of commercial trail cameras.  Cognisys makes a number of “active” sensors based on “break beam” and (now) lidar for use with DSLR-based camera traps.   You would also have to come up with your own no-glow lighting source, and hack the DLSR camera to remove the (built-onto-the sensor) IR filter.  In our experience, these sets are 10x more expensive and time consuming vs. commercial trail camera sets, and are only justified by the potential for (a few) superior images. 

The species-specific triggers and sets mentioned on this thread seem like a better option. 

Avoiding daytime false triggers: All the commercial trail cameras I’m aware of have a single type of trigger sensor. It is based on a Passive InfraRed (PIR) sensor and Fresnel lens.  Apps, Weldon and McNutt cover this admirably in Peter Apps, John Weldon McNutt, “How camera traps work and how to work them,” African Journal of Ecology, 2018.

These sensors trigger on changes in certain areas of the thermal field – in practice a combination of a heat and motion in one or more detection zones. They are not decomposable.

Some cameras (e.g. Browning SpecOps, and maybe the Dark Ops Pro?) allow you to set hours of operation so that the camera only triggers at night, for example.  This would cause you to (for sure) miss “off hours” appearances by your target species, but would avoid daytime false triggers. 

No Glow Image Quality: The good news about longer wavelength “No-Glow” flashes is that animals are less sensitive to them. The bad news is that the CMOS image sensors used by cameras are also less sensitive to the longer IR. Less signal leads to lower quality images.  Others have mentioned adding supplemental no-glow illumination.  An easy way to do this would be to set up two cameras at each of your sites.  When they are both triggered, each will “see” twice as much illumination, and image quality will be improved.  Browning SpecOps models (at least) have dynamic exposure control on video which allows this scheme to work (with only a frame or two of washout) while the algorithm adjusts exposure). For an example of this effect, see opening porcupine sequence in our video at https://www.youtube.com/watch?v=itx7KnlxKS4