I killed the strain gauges of one axis of the pointing stick prototype, so I put together a neater one. This one has the magnet wire connect straight to a rigidly mounted thicker wire, which will hopefully make it a lot less fragile!
I think if I do a proper version of this, it'll need to use something surface mount, because this took hours.
Kitchen timers have always annoyed me - there's always something about them that doesn't feel quite right. I'm working on an improved one that works how I'd like it to.
The plan is to get a first prototype working and start testing it, then make a blog post. The problem with that is that I don't have a blog right now! I think there's going to be a lot of yak shaving in this project...
Added a post to my blog about designing the 3D printed IKEA pegboard mounts: https://www.gbryant.co.uk/posts/2020-06-09_pegboard-mount/post.html
If it seems familiar it's because I wrote it as a blog post but didn't have a blog so posted it on Mastodon.
So the next resin I try will be something that's 1:1 or 2:1 so that I can accurately measure both amounts.
My 3D printed mixing stick worked pretty well though!
The first casting of polyester resin is still liquidy, despite using too much catalyst. It's a shame but I'll just leave it in the mould and see what happens over time.
The second casting I tried was into a keycap mould I bought. I actually used the right amount of hardener this time and it seems pretty solid!
The problem I ran into is that the amount of resin I need to mix (~25g) requires so little hardener (~0.5g) that it's hard to get right, because you can't put in less than a drop.
Looks like the open source trackball world is starting to get some alternatives to the Ploopy!
I wanted to try casting clear resin, so I bought some moulding silicone and some clear polyethylene resin! The mould of these coins turned out pretty nice - I don't think there were any bubbles on the surface.
I put way too much catalyst in the resin so we'll see how well it cures. Apparently it's likely to crack so I'm not very hopeful. But it's only a first attempt, and I'm expecting to fail a lot!
The polyester is stinky stuff.
Aaand that's a PCB. I would check it more buuuut... yolo
Maybe on the next version I'll make sure the connectors are actually on a sensible 0.1" grid. Oh and less of a routing clusterfuck.
Successfully making more of a mess. This is what happens when you don't plan anything, just make it up as you go along.
So far the layout is just a mess but I've kinda grouped stuff to get an idea of the size needed.
I'm going for TSSOP packages, which are smaller and more of a challenge to solder than I'm used to, so that will be fun.
Schematics for the pointing stick are coming along! It still needs some tidying up but I think this is enough to get it working.
With this I can make a ~40x40mm board that can be used over USB as a trackpoint, or over i2c with a keyboard, or just output raw analog voltages.
If this works, the version after this could use the PCB itself as the beam the strain gauges are mounted to!
Also I can't delete my Apple ID without phoning them because it has a balance of £0.09.
I got VIA pretty much working with my grid60 keyboard. It's pretty crappy how limited the documentation is, but thanks to MechMerlin's videos on youtube I got it working!
@kemonine Any idea wtf is going on with VIA? It looks like it used to be open-source or something, but their github doesn't have anything except binaries. It looks like the only documentation on adding keyboard support to it is MechMerlin's streams on YouTube.
Just spent most of my day off work finishing up the blog post on my various experiments with the Ploopy trackball.
I've decided it's good enough to upload, so here it is:
The MCP4251 digital potentiometer worked pretty well for adjusting the opamp bias! Unfortunately once I tried to get it to adjust automatically, some connection somewhere went dodgy and I couldn't get any further. I think it's time to make a proper PCB for this.
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