OWL Community Builds

[geezacoleman]

If you're building an OWL or have built one already it would be great to learn more about how you plan to/are currently using them and which country you're building it in too!

You could share some photos of the build process, completed versions mounted on equipment or share your experience with the assembly.

We've built them in NSW and WA in Australia for the backs of vehicles and on robots, but it would be neat to learn more about how others might be using the OWL.

[Minorplanets76]

Well that's a coincidence!
A miracle arrived today from Little Bird Electronics with a new global shutter camera. This will be the start of my Owl test rig.

I have been running AgOpenGPS for some years along with auto steer and section control on a modest 6m Hardi boom. I recently got a new tractor which is being treated to hydraulic steer valve upgrade and new boards. Once that's implemented I'll be looking at this project.

I had a look at a Weedseeker unit at a clearing sale recently which reminded me of this project. That was using teejet solenoids on standard teejet bodies. Very expensive yet very simple concept, so I've ordered a selection of solenoids with a view to adapting a similar system to make it easy to give any boom as many sections as it has nozzles.

I'm in the Gunnedah area NSW. You're welcome to have a look if you don't mind a short detour from the Uni farm sometime.

[geezacoleman]

This is great news! Glad to see some Raspberry Pi boards starting to become more available again. Will be great to see how the 6m rig comes together and would also be neat to see it integrated with a AgOpenGPS tractor once you have it up and running.

Do you think you'll use the new libcamera/Picamera2 instead of the old version? That's something we need to get sorted out, the conversion doesn't look too tricky and will future proof the OWL substantially for other camera systems too.

[Minorplanets76]

Yes, I will need the new version for the GS cameras. For testing I didn't manage to get it to work using the OWL img despite quite a bit of updating and installing what Google reckoned I needed. With a fresh install of the Bullseye release it just works.

Solenoids arrived today. Made me realise how power hungry they can be for a pretty low force. I'm realising why the commercial ones able to do pwm are expensive. Will do some tests and see if I can get something working.

[ahogan27]

Have finally started on my build. Based in Orange NSW, without immediate access to spraying locations, so am building a bench testing unit. Plan is to just use lights to replicate solenoids. Hoping to contribute to some of the coding, in particular inclusion of GNSS to the system.

[geezacoleman]

Very nice set up! Those 12V lights are really handy for testing/diagnosing issues, particularly when you don't want to get water everywhere.

How was the build?

[ahogan27]

Build went well. Biggest challenge was getting the camera focused. Didn't realise that the flathead screw on the lens mount was to tighten the back focus adjustment ring, so made the assumption that the back focus had to be screwed all the way in (otherwise it was noticeably loose). Once I figured that out I was able to get the focus sorted quickly.

Also, didn't seem to be clear in the documentation - what's the command to close out of owl_focus?

[geezacoleman]

Good point - I might add that to the documentation. I remember doing that as well. The lens also has somewhat confusing aperture and focus rings that don't seem to match the hold screws.

Should just be able to press ESC after clicking on any of the video windows or Ctrl-C in the terminal. ESC is the neater option though.

[ahogan27]

Thanks, for out by Ctrl-C but it didn't feel right, will use ESC next time.

[ben-at-agtechbydesign]

Built an OWL system to attach to a repurposed quad-bike sprayer. Fed from a constant pressure pump with a recirculating feed loop to manage system pressure. We mounted the solenoids onto 4040 aluminium extrusion so we could play around with different nozzle spacing and different spray fan sizes, in combination with different camera combinations. Really have to commend Guy and everyone who has supported OWL for building an amazing system with excellent documentation.

[geezacoleman]

Thanks for sharing Ben! I'm glad the OWL helped kick off the WeedSelector and get you guys started. Keep us updated with how you go!

Any suggestions/improvements for the build/design etc?

[ben-at-agtechbydesign]

Absolutely, will do.

We found the mechanical assembly very straightforward, however it took some poking around and external research to find out RaspiOS Bullseye (and now the newly released RaspiOS Bookworm) are less compatible with the Raspberry Pi HQ Camera. Support for the 'picamera' library has been removed on Bullseye and later, so using Buster fixed our camera detection issues.

If I was to change anything I would add a section in the software section of the readme explaining what version of RaspiOS to use and why, and potentially a reputable download link as a version of Buster was kind of hard to find online.

Apart from that, the quality and care that has been put into this project is amazing, keep up the great work!

[gnaegit]

I also started with the newly released Raspi OS Bookworm and then had some problems when installing all the packages according to the guide. I managed to install (almost) all of them (or newer versions). But finally when it came to focusing the camera I got an error. I was not sure if it was due to a problem with one of the packages or due to detection of the camera. I could not find the camera in the Raspi configuration under interfaces. Then I changed to Buster as the guide proposes so. However, I still have some problems installing the opencv-contrib-python package as the numpy wheel can not be build. I agree that it would be nice to make it clear what Raspi OS should be used and if newer OS's would be supported in the future.

[geezacoleman]

Yes - this is a great point. Thanks for the feedback. The latest RPi OS won't work primarily because of the clash with picamera and picamera2. I would recommend using the existing image and updating it.

Adding picamera2 support and therefore updating it for Bookworm and the Pi 5 is underway. Picamera2 really makes it much easier to use a range of cameras including the Arducam. It's something I hope to have done in February next year - the next couple of months are quite busy unfortunately. In any case, I'll add a clearer note to the installation instructions about this.

[bassyboi]

working on a boom that that will be able to extend size just bolt on and go will come up with a foldable section this is a 1m part atm

[bassyboi]

[MisterHW]

Inspired me to have a look around for scaffolding truss modules. There's also a surplus market for them:

I presume the average OWL user has means to fabricate their own solution. Sharing this in hopes that it may help lower the barrier of entry regardless. Can see how these would allow to focus on the joint parts and preserve a degree of modularity for future extension / adaption.

[bassyboi]

Should work mate!! Yes I was thinking about how I could make it like a boom sprayer that could be made for everyone!! Look if you really want me to I could come up with something if I get the dimensions like pipe wall size and that!!! What size boom you would like!!! I did do a trade as a fabricator/welder so I’ll try make it as easy as I can to fabricate… are the scaffolding pretty common sizes??

True about trying to make the entry level as low as possible!! You have definitely given me some ideas

[bassyboi]

bitta promo for the page

[geezacoleman]

Epic!! Is that a boom you're going to have built? Truss segments are a great idea @MisterHW for DIY options. For a 12m folding boom I'm trying to figure out how to neatly tuck the units away.

Some low cost, small booms are available like the Croplands MBX series