Show newer

Had a really nice day out with a couple of friends from uni, following a spy-themed treasure trail around a nearby town. It was a cool way to see some details that we'd never have noticed otherwise. Good fun even though the clues are aimed at kids and we're all in our mid 20s!

If you're in the UK I'd recommend taking a look to see if there's anything nearby: treasuretrails.co.uk/

Another problem is that the prints are failing a lot, because the on the right, the pink part only has a tiny surface touching the build plate. Looking at it, it doesn't need that much of a fillet, so I'll reduce that and hopefully it'll work.

Show thread

Recompiling FreeCAD got it working again. Here's a cross-section of the button holder design. The pink and green parts are printed in one go, the grey part is the microswitch.

There are a few issues with this design. It's a little scratchy where the layer lines of the two parts rub together, and it varies from print to print.

The microswitch is mounted to stripboard glued to the bottom, which is not great because the glue is all that stops it falling off. Ideally it would be held by some plastic.

Show thread

Nice to see my CPU actually being fully utilised for once (I don't compile things very often)

Deleting and redrafting lost the images the first time >:(

I'd post the switch assembly design from FreeCAD, but it won't start properly since the last update.

Show thread

I'm not convinced by the touch buttons on the electro-sax, and I had a few microswitches laying around, so what about using those for the keys?

I 3D printed some little button assemblies and a frame to hold 4 of them in place. I didn't try a print-in-place pivot on the buttons - instead there's a hole to insert a small bit of filament.

The action of the switches is quite smooth, and maybe low enough pressure to be usable. It's worth a try.

Show thread

On this one I added a second octave key so there's now both "octave up" and "octave down". So it has a way of getting to the lowest notes that would typically use pinky keys. It's still missing the high end that's normally done with your left palm, so maybe it needs a third octave key.

Show thread

It didn't take long to build a touch-sensitive version of the electro-sax! This is definitely nicer to build than soldering a key matrix with diodes, but the analog sensors aren't quite as nice to deal with on the code side.

The key thing is that it works! I'm not actually sure whether I prefer the buttons or the capacitive sensors. I need to tweak the sensor calibration a bit before I'll be able to tell.

Show thread

A bit more playing around with touch sensing on the Teensy. It's a little stripboard keyboard which can only play a C arpeggio! It only uses one touch sensing pin along with a 4067 analog multiplexer to get 16 touch inputs.

That's enough for all the keys currently on the electro-sax, plus two more octave keys and... I dunno, two more to do something.

Show thread

ace ex: I feel like this is how mastodon works for you

me: that would be correct yes 😌

i'm here on the timeline of mastodon dot social, a federated, decentralized social media platform

Taking a break from breath sensing to try out the Teensy. The built in touch sensing is very neat!

I might use this with an analog multiplexer to make a touch-sensitive version of the electro-sax

Show thread

Q: If you are making a series of tutorials on impedance matching, what should you say at the beginning?

A: Stay tuned!

Maybe this is the cause - the response is really non-linear. It jumps very slightly above the 0 point, then sits level as I keep blowing more, then suddenly jumps up before increasing linearly.

The other graph is me playing a piece - it looks alright to be honest, so maybe it's not the non-linearity, it's something in my program?

Show thread

New electro-sax breath sensor is attached. It looks pretty good but unfortunately it's kinda bad :(

It has the thing where if you start blowing suddenly the note is really quiet. I'm really not sure why. Got to figure out the actual cause.

The feel of the mouthpiece is good, but I need to be able to twist it to an angle for it to feel right. Aligned with the sax means I need to twist my head.

Show thread

#Fedivision announcement!

The Fedivision Song Contest (#FSC) will accept entries until Friday, 28th midnight CEST, so we have enough time to find collaborators if needed (#FedivisionCollab), come up with beautiful songs for the fictional country or faction you would like to represent.
Also, we won't run into scheduling troubles with this other music contest named #ESC.
\o/
Spread the word, have fun! I'm looking forward to the weekend of the 29th/30th when voting will take place!

DOUZE POINTS!

Show thread
Show older
Mastodon for Tech Folks

This Mastodon instance is for people interested in technology. Discussions aren't limited to technology, because tech folks shouldn't be limited to technology either!