- cross-posted to:
- traaaaaaannnnnnnnnns
hello comrades! It's been a minute! I'm back with my first tech update since upending my entire life and getting re-settled! Let's talk 
What I've been up to
See for yourself, pictured is the first alpha of the Sphynx Lite. Schematics are on git, go check it out (and if you want to set up KiCAD to view or edit but aren't quite sure how, say so in the comments and me or someone else will help you out!)
Issuing guidance on the usage of these things is complicated. I'm always going to be a little apprehensive recommending that people use this, because I'm a very cautious person. For now, I think my official guidance is:
- you should understand the circuit
- you should have basic debugging equipment
- you should have the time to work with it extensively
- if you meet all of the above, I provide this with no warranty and no guarantee, knowing you full well have ideas as to what you might want to use it for
- If you have a decent working knowledge of electrical engineering and want a walkthrough, I might make a Matrix so I can actually communicate with people looking to get it going??
As it gets more mature and I revise and revise until I drop the alpha, I'll trust it more.
This was a push across the finish line. I optimized for getting something testable done with the correct topology, layout is a little dicey (cut off silk screen in the bottom right 
) and subject to change, I just needed something to test on. I was gone for over two weeks from my last post here, mainly because it was just a lot of work with nothing intermediate to report. But now it's here! This has all the working parts of the last boards merged into one, with the new additions of:
- power conditioning
- 9V battery holders
- additional safety measures, like the redundant current limiting JFET
- configuration jumpers! and test points!! !!!
Oh, and I whipped up a cute lil logo. :3
Schematics
schematics in here
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Show
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Board Layout
board layout in here
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Board Renders
board renders in here
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Show
Next up
I have a lot of really good work from y'all that I need to capture and incorporate. Particularly, my immediate plans while this board is fabricated and shipped are to:
- Incorporate @ComradeEd@lemmygrad.ml's patchset porting the site to Jekyll - really thank you so much for this, I've been extremely focused on the board, and now that I have a minute, I can get the site going so I can use it to show off, post guide, aggregate educational resources, etc. This is going to be absolutely necessary for the project to have the reach and accessiblilty I'm hoping it gets. Thank you.
- Build a probe per @YearOfTheCommieDesktop@hexbear.net's work into coming up with a probe holder. I have a handful of the Yasutomo's to experiment with. This is going to be a game changer, currently I'm doing self-work with an alligator clip and it's extremely irritating. An ergonomic and reproducible probe with an extremely cheap parts list is critical for the project to function. Thank you.
- More of you provided meaningful help than just these two, these are the two who's work I'm directly interacting with this minute. Thank you to everyone who has stopped by and made suggestions, I've read them all.
The next post will be me building this out and reporting on how well (or whether) it works, and documenting changes for the Lite Alpha 2.
I also badly need to make a BOM. With some effort, anyone who's built a board together can buy all the parts for this and make one, but it'd be a thousand times easier if I just made a single cart that you can buy that includes every single component. If you want to make an alpha board for fun or debugging, maybe hold off until I have that out.
Any ways to help?
Honestly, those of you who are following this pretty closely have a good read on what's going on, what's needed, and what's upcoming - keep being interested! If anyone wants to make one, I do recommend waiting until I release a BOM, but very soon we miiight be at the point where other people besides me get one of these in their hands.
I could also use some polish on the logo. It's fine, but it could be cuter, and the lines are a bit funky. I'm going to put SVGs on git soon and if anyone feels like cleaning them up, rearrange the kitty cat face so it's cuter, fixing my wonky paths, let me know!
Also, and I simply cannot stress this enough - when I've been exhausted, when I've been deep in executive dysfunction, when I've been not feeling up for it, I've read through all your encouragement and support throughout the duration of this project and it's helped me to keep pushing. I would unquestionably not be this far without y'all. Thank you all so much. 
As always, stop by, hang out, say hi, ask questions, tell me what you've been up to, design review me, however you'd like to be involved is good by me! I'm thinking I want to make the expected cadence of posts once every two weeks, just because I'm busy and I don't want to cause alarm when I miss a week. I can always surprise y'all with more frequent posts too.
P.S. - I have no hair regrowth in test areas. 
@YearOfTheCommieDesktop@hexbear.net - How did you get the collet out of the Yasutomo Artist Pencil 1.1mm? I'm genuinely amazed at how well it holds a probe and how easy it is to install one, but I can't figure out how to get the collet out of the body of the pencil for soldering a wire on to. What did you do there? I tried pushing it in the tip and out the back thru the lead cylinder but I'm scared I'm going to break something, I already put a decent amount of force into it
yeah that's definitely the toughest part... the collet needs to come out the front of the pencil, it can't fit out the back. It is barbed (visible in this pic if you zoom way in) so it digs into the plastic pretty damn well, but it can be pulled straight out.
I basically just used brute force. it should be pretty safe to pull straight outwards on the collet by the ring part (the part that moves freely) since that way there's no bending, its all metal on metal, in tension, and the thin members of the collet are pulled snugly together and stressed evenly. you can use a small pliers but you don't want to squeeze too much. either grab the ring head-on and squeeze enough to get a grip, or use a sufficiently tiny pliers to grab from the side between the spring and the collet ring, not squeezing basically at all and just hooking the jaws of the pliers under the ring and pulling out. Some wiggling/wobbling the collet (while still pulling outwards so nothing bends) as you go could help but will probably make the fit looser when you go to put it back in so don't go overboard.
I don't think there's a great way to push it out from the rear either, since behind it there's a narrowing of the hole in the plastic to about the same size as the one on the back of the collet. Maybe if you had just the perfect 1.5mm rod or something but it would probably just buckle.
this is definitely quite in there lmao
What tools did you use? I'm working with what I have, which at the moment is an allen key and a cotton swab with the ends cut off. Basically, I put the cotton swab stick down the lead chamber and I'm pushing it in with the allen key (the allen key on its own isn't long enough to reach the back, I added the cotton swab stick for more reach). So, that is to say, I'm now trying to push the collet out the front from the back. I'm not seeing a way to grab the collet, it's pretty deep in the tip of the pencil. Does this sound like I'm on the right track?
edit: just re-read your post, I missed that you said pushing it out from the back is a no-go too. oops. Did you have to do anything to the plastic body of the pencil? It looks pretty intact from your photos
edit 2: I got it
I think trimming the end might actually be mandatory. It wasn't so bad, I did it with a swiss army knife. The result is pretty clean looking. I just trimmed back enough of the tip so that the shoulder of the wide part of the collet is all the way out when the end cap is pressed, and then from there it was easy to get under it with a pair of tweezers and pull. I bought a few of these, so I'll do one more and take good photos. It works beautifully and I'll let you know when I've used it for the first time!
Yessss! So glad it worked!
To explain the confusion: I actually pulled the entire lead tube out before separating the collet from the lead tube, (the main body/grip of the pencil is a separate piece of plastic!) so I had plenty of room to grab the collet with tools. However your way might be better, since as I recall it took a fair amount of force to pull the lead tube out the back, and after doing it a few times the two halves no longer seem to click together and stay very well.