Using Trail Camera to Trigger a DSLR Camera
One of the challenges facing the homebrew DSLR camera trapper is finding a good PIR trigger sensor. In our experience, there is no standalone PIR sensor that matches the cost effectiveness, physical robustness, sensitivity, and false trigger rejection of the sensors integrated with the best commercial trail cameras. Whenever we’ve co-located one of our Browning trail cameras with the DSLR in a set, we always seem to get more triggers of animals, and fewer false triggers with the Brownings. In this post, I describe a system for using a commercial trail camera to trigger a DSLR camera. A Browning BTC-7A (Recon Force Advantage) also takes its own video or photos. For those interested, I have also written Deep Tech: Trail Camera PIR Sensors which gives more details on how these systems work in trail cameras.
The complete solution I describe here is based on: firmware customization tools I introduced in IR to White Flash Trail Camera Conversion. See: DIY: Using Browning BTC-7A to Trigger DSLR for give instructions for replicating this solution for those interested.
“I thought you said this was hard?”
On a facebook post, Geoff Jansen recently asked whether he could repurpose a trail camera sensor to trigger a DSLR camera. I commented that it would be “hard” — since sensor, optics, electronics, and firmware are tightly integrated with camera itself, and almost impossible to separate from the trail camera itself. Janet recently posed the same question, slightly differently. “If we are using a regular trail camera anyway on our DSLR sets (to check the DSLR triggers), why don’t we use the trail camera as a trigger for the DSLR?”
OK — so eventually I can take a hint.
My solution makes no physical changes to the trail camera itself. It does require modifying the camera firmware. The key bit of technology that made this “hard” solution possible was a set of software tools I developed for an another project (IR to White Flash Trail Camera Conversion) which allows me to add custom functions to the Browning BTC-7A firmware. It took several months to prototype these tools, but now that this work is done, it is relatively easy to add new functions.
Trail Camera Trigger DSLR in the Field
The video below features some examples for this system in action. I have edited in footage from both the DSLR as well as the Browning Trail camera videos. We’re still tuning some of these sets, so the DSLR shots aren’t perfect. For example, I inadvertently set the shutter speed for the possum set to be below the camera’s sync speed, leading to a dark band at the bottom of the DSLR frame. But they do show the timing of the trigger for the DSLR
Video from BTC-7A as it triggers a homebrew DSLR. The BTC-7A triggers the DSLR at the same time it starts taking video, so you can see the flashes and hear the clicks from the DSLR in the video. Note that this trail camera has also been modified to take color videos as night using a white flash as described in IR to White Flash Trail Camera Conversion
With Cognisys SCOUT Setup
In the Bear and Beaver clips, we used a Canon 80D in a Cognisys enclosure with Cognisys Xenon wireless flashes. Note that with the settings we used for the SCOUT controller, it waits until the flash devices are “ready” before activating the shutter release. This is the case, apparently, even with the DSLR set for “slow continuous” shutter release mode. The result is that all the photos are well-lit. However, there are delays (including for the first shot) while the flashes are charged.
If you look at the first DSLR photo in the sequence, you will also notice that it is slightly out of focus. This is true even though the camera is set to “Manual Focus”. I believe this newer 18-55 mm EOS kit lens needs to “wake up” to get the focus right. Note that subsequent photos are all in focus.
With Canon60D Homebrew
In the Oppossum clip, we used a Canon 60D with a homebrew enclosure. There is no “controller” per se. I set the camera to “slow continuous” shutter release mode. The BTC-7A continuously activates the shutter release during the entire 10-second video. The camera takes the first photo almost immediately, but it is dark because the flashes (SB-28s) are not yet “awake”. It does “wake the lens” up, so that by the time of the second shot, roughly a half a second later, both flashes are working and the photo is in focus. There is some fading of the flashes over the next several seconds worth of photos. Towards the end of the ten second sequence, one or both flashes cannot keep up, leaving the photos partially lit, or not lit at all.
Based on this experience, we plan to limit this set to 5-second videos. This will result in 5-seconds worth of continuous shots by the DLSR, which is short enough for the flashes to keep up. We will also set the Browning trigger delay to 5-seconds. This should allow the flashes to completely recover between triggers.
Solution Summary
This solution contains two elements:
- A custom firmware image for the BTC-7A (Browning Recon Force Advantage) which flashes the bright red “Aim LED” whenever the camera is taking a video or photos.
- A cable with a photo transistor on the end which triggers a camera directly (e.g. Canon 60D), or which triggers a camera controller (e.g. Cognisys SCOUT).
The photo transistor mounts to the face plate of a security lock box for the BTC-7A, creating an optical coupling between the Browning camera and the DSLR. Light from the red aim LED on the Browning activates the photo sensor mounted right in front of it and the photosensor triggers the camera. This has the significant advantage of not requiring any physical modifications to the trail camera itself.
Conclusion
With the help of some software tools I developed to solve another problem, I was able to modify the firmware of a Browning Recon Force Advantage (BTC-7A) so that it acts as a trigger for a DSLR-based camera trap in addition to taking photos or videos. A 3D-printed housing attached to the BTC-7A lockbox holds the photosensor in place over the camera “aim LED”. A short cable connects the photo-sensor to the camera remote shutter release, or to the RX input of the Cognisys SCOUT camera controller.
Using the BTC-7A in this way promises to improve the lumber of animal captures in our DSLR cameras. Unfortunately, it is not a cure-all for the many challenges facing the DSLR camera trapper. There are still issues of timing related to: waking the DSLR up and achieving focus; energizing the flashes; etc. All of these can increase the critical effective delay to first photo. Setting the trail camera to “video” mode, at least, and looking for the flashes and/or listening for the shutter release in the resulting videos gives a good sense of the source and magnitude of these delays.
If you are interested in trying this yourself, I’m looking for Beta testers for my DIY post on this topic. Please let me know in comments below.
What a great set-up! I love your book too.
Thanks, Karen. We’re glad your enjoying Janet’s book, too š
I am very interested in this set up. I have used at least four different motion senors, some take about six seconds from movement in front to the camera to fire the camera, some a second or two, but the faster ones don’t seem consistent. I have three Camtraptions sensors which I haven’t used in over a year since they take closer to six seconds. I would be happy to buy what ever equipment is needed to test the set up, I likely already have most of it.
Great! I will contact you via email shortly
Very interesting, awesome work! Howād you get and modify the browning software?
Thanks! I describe the process in a little more detail in an earlier post IR to White Flash Trail Camera Conversion. The basic steps are:
The core process of reverse engineering the firmware is like completing a complicated crossword puzzle: you look for hints in the existing code; make guesses about how things might work; fill in those guesses; and use those to make new guesses. A set of guesses which are self-consistent, and which work, are keepers.
I’d be interested in testing this too if you’re still looking for testers.
Cool. I’m currently tweaking the design to avoid (of all things) a “run-on” trigger situation. Will email you with an update.
Iām interested. I built my own PIR sensor which has been very effective but Iām always looking to improve.
Cool. At this point, the key to this project is getting a Browning Recon Force Advantage (BTC-7A) to use. Unfortunately, this is the only model (so far) for which my firmware hacking tools work. But now that Browning no longer manufactures this camera, it can be very hard to find. I am considering porting my tools to a newer (available) camera, but haven’t found one that I really like yet. It’s a fair amount of work. So… if you have, or can get hold of a BTC-7A, let me know. Else, I will add you list of subscribers waiting on a newer camera.
Great idea! Iād you get the firmware back working for the Browning BTC-8E-HP4 (spec ops elite)I would be interested! I did wonder if just enabling the āmotion testā which lights the AIM LED when movement is detected would work effectively as well – or if that just lights with all movement and the āsmartsā of the camera wouldnāt be used as they are if the firmware has the LED come on only when the camera chooses to begin recording?
Thanks. I’m not sure which model I’ll be hacking next — or exactly when š — but I’ll refresh this post if I add any other cameras.
As far as the “aim test” goes. The issue is not really missing smarts. It PIR trigger is the same whether it turns on the camera, or turns on the LED. The bigger issues is that when in “aim test mode” the camera never goes into a low power state between triggers — it stays “on” all the time, which quickly (in less than day) draws down the batteries š Secondarily, in the aim test mode, the camera isn’t taking photos/videos, which is a nice feature of the current hack.
Thanks for commenting!
Thanks, for me actually as I want to use it in my ābackyardā (semi rural Australia) refreshing th batteries each day would not be a negativeā¦. So I might try to make the light sensitive trigger cable and try it out.l.
Yeap — that could work. You would definitely want to get some rechargeable cells. The newer Browning models now support NiMH AA cells, at least. You will also find out exactly how long whatever batteries you use will work in the “aim test mode” — my earlier suggestion of a “a day” was approximate (perhaps optimistic). If your are interested primarily in night shots, this method will also trigger off the IR LEDs with an unmodified camera in photo/video mode. I’m about to get the 3d-printed part that holds the photodetector and a small PCB back from the fab before publishing the “DIY post” for the adapter. Let me know if you’d like to see a pre-published (even more at your own risk than usual) version.
Hello and thank you for a wery interesting post.
I my self has been thinking of a similar way to trigger a DSLR but I have always been thinking of connecting by wire connections.
Do you sell your setup? Or can you provide links on where to get the stuff needed? I’m a Nikon shooter if that matters.
Best regards Conny (from Finland)
You’re welcome – glad you found us. Yeap — going in with a pair of wires is another route. I decided against this because I didn’t want to breach the plastic enclosure to get the wires out (and possibly wreck the moisture seal). Also, it turns out to to be a little tricky to figure out where exactly to put the wires. In any case, the optically coupled solution seems to work well.
When I first published this post, I had in mind to link it quickly to a detailed DIY post. I actually have one in progress, which I will send you. I have delayed publishing more broadly for two reasons: Browning no longer makes the Recon Force Advantage (BTC-7A); and I am still doing some tweaking on the design of the 3d printed enclosure for the light sensor that mounts to the camera.
I haven’t tried with a Nikon camera, but I’m pretty sure it will work, albeit with a different (widely available) shutter release cable adapter made for Nikon.
Really enjoyed this write up. I would like to try this by triggering off the IR LED’s on an unmodified trail cam. Would you please share with me the details from the unpublished DIY you mentioned in other comments?
Glad you liked the writeup. (at your prompt) I finally got around to publishing the DIY which has been in my draft folder for over a year now (?!). Long enough ago that I’ve forgotten why I didn’t think it was ready :/ I just skimmed over it again, and it looks pretty complete. Hopefully “good enough” : https://winterberrywildlife.ouroneacrefarm.com/diy-using-browning-btc-7a-to-trigger-dslr/
Very interesting projects. Can you share any details on the firmware hacking software ?
Sure. Will respond in email.
Awesome info, I would love to try this with my ancient but beloved fuji s5 pro. thanks
Cool. I have recently ported the firmware to the currently available Browning Elite HP5 series cameras. I expect to have a post with a link to that firmware out soon. I did notice that the “aim LED” placement on the HP5 is different than on the Advantage, and may require some tweaking of the photo sensor housing.
I feel like there has to be an easier way to do this.
I have been thinking on using my trail camera with my dslr for a while, and the idea in my head is to combine a dslr trigger cable to the trail camera. like if the camera wakes up to take a photo that will send a signal to the trigger pin on the dslr and also take a photo.
the thing i don’t know is, where i would have to solder that wire in the board to get that signal.
I thought of hardwiring a trigger wire directly to the PIR sensor. There are a few issues which make this difficult. As you say, it’s pretty tricky to figure out exactly where to put the wire. It depends on the PIR sensor type and the camera manufacturer. The other issue is getting the wire “safely” out of the camera without damaging the moisture seal. Finally, the camera is expecting a specific signal — typically an open collector pulldown transistor, which may not be possible without additional electronics. Given all this, I went with the optical connection described in this post. I have recently ported the firmware necessary to the (currently availalble) Browning Elite HP5 series cameras, and hope to have a post out soon with a detailed “how to”.
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