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Comment by davidhyde | Hacker News Reader

Loved the write up, well done to the author. I get the same feeling building stuff with freecad and then printing it. Feels like there is no limit to what can be done. After going through the growing pains of designing stuff that was just poor and difficult to print I’m now confident enough to send it to be printed by jlcpcb or pcbway. And when they tell me to accept the risk of a failed print then I think, “I feel your pain, good luck”. So far I have never gotten a failed print back. Maybe a little warped but way better than my attempts. If I never have to use my large resin printer ever again I will be happy.

On the pcb front, I dread going through those final steps in the pcb ordering process. No matter how many parts I preorder, there is always something that is unavailable. So much churn in component availability.

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Thanks, glad you enjoyed this. It's good to be in a place where you're confident things will turn out alright when you send your designs halfway across the world to be manufactured. I've so far only had positive experiences with JLCPCB, especially with issues that turn up during their review process. I forgot to add a fillet around the edge where the DEC axis sticks out of the tube and they sent me a quick message to say "We can't guarantee a 100% right angle here cause of the minimum radius of our bits". I assumed they would just gloss over this and manufacture it anyway, but they gave me a chance to review it just in case it was important to the design (it wasn't in this case, but still). On the PCB side, I used a plugin for KiCAD that automatically generates the production files and the bom.csv - It's really critical to review this when you load it into their tool because the automatic recognition/matching with components sometimes has mistakes in it.

I built a small two axis direct-drive mount (https://mjbots.com/ controllers are great) to track satellites and aircraft with an RF antenna. One of the things that stood out in the article for me was the yolo send to JLCPCB. It spoke volumes about your confidence in the CAD design, maybe one of these days I'll get there hahaha.

Great design and writeup btw, it looks as good if not better than most of the commercial designs out there. You might enjoy Bruce Van Deventer's vids on youtube: https://www.youtube.com/@djcheckonetwo/videos (direct drive mount with 26 bit renishaw ring encoder might whet your appetite a bit)

Thanks for the compliment and links! Can you tell me more about the aircraft tracking? I've been toying with the idea of being able to select a nearby airplane on flightradar24 and instructing the mount to follow it as it comes into view. Not sure how I would even begin building that.

You could actually build a self-contained unit with a raspberry pi and a rtlsdr based receiver. They do a great job picking up ADSB directly from aircraft 100+ miles away.

You'd just need to write some glue code to take the ADSB streams from a given plane (could pick based on area or strongest signal or whatever) and convert that to alt/az from your reference frame to feed the motor controllers for tracking. Your mount would clearly be adequate for optical tracking so you'd want to add some smoothing and likely some kind of tracking corrections/trim but you'd be close right off the bat.

Forgot to mention, if you hook that ADSB receiver up to flightradar24 full time they (used to at least) give you a free membership.

https://www.flightradar24.com/share-your-data

I’ll look up that plugin, thanks!

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