What steaming pile of sacrilegious butchery is this?

[memecode]

Today I drove out to the edge of the city where there is a timber store that has all sorts of interesting wood. I got some ash and rosewood to practice on. I've chopped it to shape and marked out roughly where the pickups are. The plan now is to cut it like I would the real thing. And see how the mechanisms work in practice. I do already have the brass parts I need. Lots of fiddly work ahead.

 

[mayfly]

Pins and needles here! very keen to see how it goes. Please post pictures, even mistakes

 

[vernschrock]

If you’re building the body yourself, you can make a lam top the same thickness as you want your “white keys”. Cut your keys out of that lam top (using either a bandsaw or Japanese hand saw if you’re good with a handsaw) before you glue the lam top to the bottom wood. I’m assuming you’ll be using something like rosewood for the black keys; you can make the grain on those go the correct way for strength. For the white keys with cross grain, which will be quite weak, I would cut a dado on the bottom side of each key (by hand or router, or both) and glue in pieces with grain going the opposite way, to make those cross-grain white keys tough as hell. Keep in mind, you want to do all that BEFORE you cut the keys out, so you’re dadoing out of a solid top.

 

[memecode]

While I wait for some parts to arrive I've been working on a way of getting keyboard state into a microprocessor. I'm planning to use the ESP32-S2 WROOM which has 16 analog inputs, and WIFI. However because I have 30 keys on the keyboard I need to switch between 2 sets of inputs and read them independently. Sooooo, this PCB basically does that... inputs (on the left side) go into 4 chips (on the right) that in total have 32 inputs and 16 outputs and a way to select between the 2 sets. That all plumbs into the IO of the ESP32. Then in the source code, you'd select bank 1 of the inputs... read their values, then select back 2 of inputs and read their values. Then put all the values in a UDP packet and send it to the laptop via the WIFI.

My first attempt quickly ran into problems. But I was making the routing more difficult than it could be. So I rewrote the schematic to have less cross overs. But all the inputs will be out of order... The plan being to sort that out in software rather than hardware.

There is another way of doing it though. Instead of switching between 2 banks of 16 inputs. Just add a whole other 16 inputs ADC chip to the board. So you'd have 32 actual analog inputs and no switching. Something that I'll be looking into this week. I may print this board up and try it out anyway, but I have a fall back plan if it doesn't work.

The keyboard sensors themselves are (at this stage) going to be hall effect switches. And I've ordered some of these mechanical keyboard switches. They are different to normal switches (ie on/off only) in that they are fully analog, and their output is a variable voltage across their 4mm range of movement. And there is a spring built in to return the switch to the "up" position. This should allow for me to look at the slope of the key's movement and calculate the velocity of the key hit. Well that's the theory.

I don't do PCB's professionally so this is a bit of a hack I would imagine. And it could probably be optimized somewhat haha. But it's really about "getting it done" rather than making it perfect.

 

[Rick]

Keep on keeping on

 

[memecode]

The lekker switches and linear hall sensors arrived in the mail so I thought I'd test them out...

 

[memecode]

Btw this is totally not dead! But I don't want to spam the board with post after post about small little steps.

So? I've made a home page for the project here: https://memecode.com/hw/teleproject/

And there is also like a log of build related posts here. That will be updated far more regularly than here... follow along if you care?

Mostly it's been getting all the electronics sorted out. But I'm rapidly coming to the end of that and switching over to building things out of wood and brass now. I will come back and post the big milestones here as well... you won't miss anything important! The next one will be the prototype working and playing notes through a synth. Probably towards the end of Sept or there abouts.

 

[alexreinhold]

Wow, I do hate this project a lot

But mad respect for doing it man!

 

[Rick]

Please post here! The nerd in me needs to know! You're the Man Meme!