This is roughly what I'm thinking for (half of) the layout. It's a little weird-looking but I quite like it.

I think I can manage to make it so that you flip the left side PCB over to make the right half. If I can get my head around it, that is.

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The full keyboard is getting there though! Some of the caps are a little loose so I had to put some tape underneath. It makes the fit of the stem a little tighter (hopefully without breaking the stem)

It's very tedious with only two moulds, and I'm out of silicone to make more. This is definitely making me want to get a resin 3D printer to make some custom shaped ones.

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Well that's a dead mould, and the last keycap didn't survive either :(

The silicone gets brittle over time. Depending on the mould, people say you can get anywhere between 10 and 120 casts from it (for something with features this small it'll be on the low end). It looks like this one only managed somewhere around 16 :(

Basically, casting an entire keyboard worth of caps is a bad idea. But I'm doing it anyway!

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Even for Windows this is a new low. Why does the calculator app break and need an update? It's a calculator‽

(Sorry about the dodgy photo of a screen, it's my work PC)

This ad goes way too hard for just a kebab shop, I kinda love it

(Also, they printed the proof copy)

Second attempt at polyurethane casting was a success! The keys are fully formed and the outsides have no bubbles.

They even fit fine on my keyboard, although one is a little looser than the other. It's clear that this resin isn't black, just a dark grey.

The working time of about 7 minutes turns out to be accurate, which is about right for the 4 moulds I have. They seemed to need the full 1 hour cure time, at the minimum demould time of 30 minutes they were a bit too flexible.

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My first run of keycap casting was a partial success, partial failure. I forgot my pointy tool to get the air out of the keycap stems so there was a big bubble instead of a stem. Other than that they formed really nicely! Some very minimal bubbles on the outer edge of the top but the form and texture look great.

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I borrowed some XDA keycaps from a friend and cast moulds around them. Now that I have some polyurethane resin I should hopefully be able to try casting some caps tomorrow! Or maybe later in the week.

The Ploopy Nano BTU mod seems to fit alright! This ball is a little too large for it, but it gets the idea across.

If you have a Ploopy Nano and would like to try the mod, there's more info available at

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Update on the hybrid thumb buttons for the electro-sax: They feel good! The way they pivot is very similar to the one on an actual alto sax, so it feels right.

The only problem is that the activation point is too late - on a real sax it's near the start of the press, here it's near the end. I can either make the travel shorter or make it more sensitive to presses in software. The latter approach is easy but has the risk of making it too sensitive and registering phantom presses.

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It's been a while since I worked on the electro-sax, but I'm back at it. I wasn't happy with the octave buttons, which were just capacitive buttons and hard to time right. They needed a mechanical element like the finger buttons.

Some quick sketching helped me figure out how I wanted to do this. It could also be 2 of the finger buttons facing each other, but that just didn't seem very nice to me.

The prototype feels good on its own, I'll have to get it mounted to the sax to figure out if it's right.

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Printed the Ploopy Nano BTU mod I designed. Now I just need to wait for the BTUs to go in it. I don't actually have the PCB or a 38mm ball that fits it, but I need to do as much mechanical checking as I can.

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The Ploopy Nano BTU mod is about as curved as I can manage to make it right now. I think this will do for a first version!

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BTU mod for the Ploopy Nano is coming along! It's definitely a lot less pretty than the original version with its nice curves. Maybe that's something I can improve on, but I was really struggling with complex surfacing.

Another row and end of the keyboard legends is done, and generated today's made up word of the day: WIRPYQUOTE.

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I was gonna do blue bits for my "symbols" layer, but it looks like that doesn't stick well to the transfer paper :(

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These legends work really nicely! The slight "grain" from the rough surface adds a nice texture.

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