Co-processor for upcoming season for vision

Could you elaborate please?

I hope you mean a and not a citrus fruit.


Limes are a pretty weak battery, I would expect undervoltage issues.


Alternatively, there’s at least one single-board computer named after a Lime .

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What kind of issues? We were able to get it running successfully on an LL2. Maybe I can help.

I believe the students doing the prototyping started with Armbian so as to have a general purpose environment in which to play with AprilTags libraries. The board claims compatibility with a lot of distributions but we have been more focused on capture and processing performance first, vs. evaluating distribution options. I expect as we progress with prototyping we will explore more how to arrive at an easily deployed solution, but right now we’re pretty much hand crafting the setup.

FWIW, we run WPILibPi on an actual Pi on our 2022 robot for driver cameras, plus the Limelight for targeting. WPILibPi is wonderfully easy to set up. If we have a chance we’ll give it a try on the Potato just to see if it even works.

We tried PhotonVision on the Limelight during the 2022 season but had multiple issues with it, and switched back to stock Limelight firmware as soon as they had the multiple-corners support we needed. I wouldn’t rule out trying it again if the issues have been addressed.

We do also have a few Romi’s for training but they have actual Pi boards on them, so we will probably not spend any time trying to make that work (at least not right away). However the claim is that the 40-pin connector block is “Pi-compatible” so there’s at least a chance it could work. Maybe if someone else tries it they can post their results here.


It certainly wouldn’t surprise me if we’d at least have to build WPILibPi or PhotonVision from source, rather than installing the provided release images. Since the ROMI is built on top of that, it may be simple enough to get that working. I’m just pondering using our ROMIs as a starting point for PhotonVision and then cannibalizing one PI for a competition robot. But, if I wanted to replace the PI, it would be nice to have a cheaper option like this. I’ve tried PV on the LL in the past as well and wasn’t happy enough with the performance, overall, but that was a few years ago. Thanks.

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We had troubles while uploading the photonvision image to the limelight

If you can compile OpenCV, cscore, ntcore, wpiutil, and wpimath (may be missing something) for your device, it can run PhotonVision. Those are the libraries PhotonVision depends on, and compiling those myself for a ODroid U4 (normally unsupported) I was able to get it to run.
Alternatively, it should “just work” on any ARM64 device out of the box that identifies as running Ubuntu 18.04 (even if it isn’t). I have run PV on a Jetson Xavier NX with zero modifications.

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Given WPILib’s dependency tree, building the ntcore, cscore, and wpimath build targets should be sufficient. wpiutil and wpinet are dependencies that will be automatically built first.

I have gotten this to work in the past by following the limelight update instructions but switching the image for the PhotonVision one. What specifically isn’t working? I know I had to try a different computer than my main desktop to get it to mount the Limelight as a media location so there maybe software incompatibilities with some programs.

What OS and software did you used?

I used windows 10 following Getting Started — Limelight 1.0 documentation.

But another windows 10 computer just didn’t work

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Okay, I’m in a similar situation. I have tried doing the same thing, on a windows 10 machine and on a mac. I’ll try strictly following the limelight imaging instructions. What photonvision image did you use? The Gloworm one? And also, did you use the photonvision beta? Thansk

I used the gloworm beta image as that has the AprilTags built in


I’ve never tried anything other than Raspberry PI boards. Do the standard PI distros just work on a board like this? Could we use the PI version of Photovision on one of these?

You likely can’t just run the pi image on any other board but they have installation instructions for other Debian Linux installations: Other Debian-Based Co-Processor Installation - PhotonVision Docs

Thank you for the info. I think for the $40 - $45 it might be worth a try. Also noticed if you order a 4 pack it puts each board at around $37.25.

If your team has the ability to adafruit has a pretty consistent stock of rpi on Wednesdays. They sell out fast but has helped me

I actually reached out to Raspberry PI themselves to request 4 boards. I stated we use them on Romis for education. Got an email back with a form to fill out for the request. Sent it and then was told someone in the states would be in touch. That was 3-4 weeks ago. I emailed them again and got no reply this time.
I have filled out the notify me on adafruit for a few different versions of the pi and gotten no emails about them ever coming back in to stock.
I do use and see they have had stock recently though.