Tsumara JD21 restoration

[resistorman]

Neato!

[Wonks]

Pretty soon you'll be able to mass-manufacture your own reliable version.

[BJG145]

I've found my niche, which is asking someone else to rebuild these gadgets rather than trying to do it myself. I can just dream up a fingering chart and a few extra functions and send off an email. Bliss.

I've requested this as the default layout, chromatic over two octaves. I think that'll fall under the fingers OK.



(By the time the manual has been fed through Wayback and Google Translate, it's difficult to find out what the original settings were.)

[BJG145]

Wiring the new buttons (and the old pitchbend/modwheel)...

[Folderol]

Some very pretty soldering there. Well done!

[BJG145]

(I can't take the credit; an acquaintance is working on it for me...!)

[The Elf]

It interests me to know how the microprocessor is being made to handle that number of inputs - I've never figured that part out!

[BJG145]

It interests me to know how the microprocessor is being made to handle that number of inputs

I'm not sure how this one has been done (I'll ask), though people often use a "button matrix".

https://www.embeddedrelated.com/showarticle/519.php
https://learn.sparkfun.com/tutorials/bu ... -guide/all

This has come together faster than I expected. It's already playable (USB MIDI) together with display and pitchbend.

[Folderol]

That looks like a nice little display. Where did you get it from?

[jjlonbass]

It interests me to know how the microprocessor is being made to handle that number of inputs - I've never figured that part out!

Most digital systems that feature more than a moderate number of user switches would organise them as a scanned matrix with each switch connecting together a unique combination of row and column.
With this sort of arrangement one could accommodate, for example, 64 switches with an 8 row by 8 column matrix. An explanation of this with a music tech relevant example can be found here. The examples show the columns being driven by microprocessor outputs with the rows as inputs.

John

[Folderol]

It's also done for low res analog controls. In the past, I've used HEF4066 to do this.

[The Elf]

That all looks baffling. One day I need to figure this out to expand the ability of the Arduino toys I make...

[BJG145]

That looks like a nice little display. Where did you get it from?

I asked about this and they pointed out this example on eBay. (They reckon Adafruit are the best, relatively expensive but cheap ones sometimes have faulty pixels.)

[Folderol]

Thanks. I'll have to check my piggy bank

[BJG145]

Received the latest update on work in progress today.

Wiring up the new display, control buttons and USB socket...













...and the hardware rebuild is done.

Just the programming to finish now...

[Folderol]

[BJG145]

This thing is currently still in Wales, where it's undergoing rigorous final testing in the hands of a gypsy jazz guitarist.

Apparently he's finding it a bit of a struggle. But...what do they know?

[resistorman]

Nice restoration! Though it seems a bit large, looks like he's holding a cyber dolphin

[Martin Walker]

Nice restoration! Though it seems a bit large, looks like he's holding a cyber dolphin

Yes, I was a little surprised at how large it was as well

[Drew Stephenson]

Nice restoration! Though it seems a bit large, looks like he's holding a cyber dolphin

Yes, I was a little surprised at how large it was as well

Maybe he's just very small?