Welcome to MiniDexed Discussions!

[probonopd]

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[positionhigh]

Hi there and gratulations to your MiniDexed Project - this really looks promising.
I am working on the gui/sequencer/tracker part for a new microdexed generation on the teensy platform, including a small tft and a touchscreen (and also, as before, 2 rotary encoders). I am not experienced on the raspberry/circle platform but i do have several pi devices available. You can see some (outdated) screenshots on my project site.
https://codeberg.org/positionhigh/MicroDexed-touch
Let me know if any part of that is interesting to your project - i think many things could be ported since you already have a text based HD44780 display in your code and we share the same "synth engine".

[probonopd]

Hello @positionhigh and thanks for reaching out.

Your project has many things I am dreaming of (more than one Dexed instance, effects, sequencer, mixer,...) 👍 but unfortunately I am lacking the hardware to try it out.

MiniDexed is running on Raspberry Pi Zero, 1, 2, 3, and 4 and we try to keep all other hardware as optional as possible, in order to allow as many people as possible to join the fun, and allow to get started with a "naked" Pi.

For at least the Pi 2 and newer I think the hardware should be capable of running multiple instances and effects. The next objective would be to run mulitple Dexed instances and TX802 style performances and effects like delay, chrous, and reverb.

So if you see some features that you could help port over, that'd be tremendous. As you probably have noticed, the developers of Circle and MicroDexed are both active in this project and have been extremely helpful.

[positionhigh]

Hello probonopd,

i have about no knowledge about Circle but i am over a year involved in microdexed so i believe i might know some things about parts of the code and its structure. Everything is deepy interwoven with the teensy audio library, so getting the core to run in circles is really astonishing to me - we also thought about making that move to Circles on the Pi but my development skills are not enough for that task and the main developer would have liked to do it but does not have of the free time to make this possible.

i fully understand your path to make as much as possible available with the bare Pi. But sooner or later, some kind of GUI structure will come up (you already have the text display if i see correctly).
Fortunatly, there are a lot of possibilities what can be done.

1. stay with the text display - you will find this is kind of limited.
2. stay with the text display and mirror it to the HDMI in text mode with more options only to see on the HDMI. (Better but not much)
3. don't bother about displays and just focus on external control over MIDI, OSC, etc.
4. have a graphic display like the ILI9341 on the spi bus and mirror the content 1:1 to HDMI (don't know if that is possible with Circle, i think you would need some basic SDL graphic stuff to get this working) . This way, the display is an extra but everything can also be used on a regular PC monitor.
5. The M8, dirty wave approach. https://dirtywave.com
   This has a local display but also can send the display content as data via USB serial to a Webbrowser or to a small PC App that mirrors the display. This is partly the way i currenty also have done it for microdexed. (so far no webbrowser but a small (100 line) C Code, that can mirror the display 1:1 to a pc, mac, linux etc. over Serial USB. The performance penality is minimal, even on the teensy with it very limited ressources, compared to a Pie. Since the Pi also has Ethernet, that also could be a option to check. But even USB2 is more than enough, to handle this task. I think this is the best option. You can keep the Pie bare but also on the same time offer a standalone graphical UI, completly copied to a PC Monitor (or a Webbrowser - think of it, with a USB-WIFI Card this would even work with a phone or a tablet) and you have the identical codebase.

If you choose something between 4-5, i think i could port over a lot of the GUI and sequencer stuff.

About the effects and instances, i am sure a Pi > 2 can handle this, probably even on 1 core.
The reverb in microdexed currently is basically this: https://github.com/hexeguitar/t40fx
It is a very good sounding reverb for its class on the teensy but very demanding on memory (on this platform). I believe you can port this to the Pi, if that not already is done - and memory on the Pi is "unlimited", in comparison.

[rsta2]

Circle runs on Raspberry Pis only. It's not planned to support other hardware.

[positionhigh]

tnx i thought that it might be very difficult but possible since the architecture seems at least partly similar. So to get my sequencer and interface things working with your Pi build i woud have to figure out if i can get a display like a ILI9341 working in this context. I looked at LVGL and it seems very fancy for simpe UIs but way too resource intense, also it does not seem to have any grid input/outputs so i think a simple, pixel based approch is still the way to go.
I understand that such things like a sequencer and on board GUI are not in your main focus. My goal is to get more to the features of https://dirtywave.com/ - Meaning multitimbral microdexed, also other synth engines, sampling, effects and sequencing in a standalone box with a touch screen or attached (USB) MIDI Controller.

[rsta2]

No, it's not that simple, and if you support other hardware, you also have to test this on any release. You need some focus and for Circle the focus is the Raspberry Pi.

Circle already supports SPI displays with the ST7789, if this helps. Programming with LVGL is special, but resources (memory) should not be a problem, because there is a lot in the Raspberry Pis. But LVGL does not work on SPI displays at the moment with Circle.

I'm not the project owner of MiniDexed, so I do not define the requirements, but supporting other synth engines and sampling seems to be a different project to me.

[probonopd]

Right now the project focus is on creating an instrument on Raspberry Pis that approximates the DX1/5/7 and TX802/816 plus mixer and effects. I'd like to keep the hardware barriers to entry really low (as in: low cost and easy access to the needed hardware) and have a "robust" instrument that boots fast and is very reliable.

[positionhigh]

totaly get it - focus on the basics first. I have so say, the fast boot is also one of my priorities - if you haven't gone the way with circles but instead booting up kind of a full linux, i would not be so much interested in the PI as a potential platform for a synth:_)
Since i can't help much on the low level stuff i will follow your progress and continue what i am doing on the teensy. Maybe in the future you will come up with some kind of "plugin" model where i can contribute my stuff as an option to your great project. All the best, cu soon!

[mrfloydst]

Hello probonopd,
thanks for reaching out! I've answered your mail but I'm afraid it went directly to the spam folder :-)
I'll post a video on your project, working on it right now.
And I'd like to join your effort by providing a manual for end users / musicians (and maybe a patch set ?)
I guess it's not possible to connect the LC display with the I2C interface mounted on it's back?

[probonopd]

Hello @mrfloydst, sorry for my late reply, went hunting for your mail when I saw your message here :-)

I'll post a video on your project, working on it right now.

Very cool! Looking forward to it.

And I'd like to join your effort by providing a manual for end users / musicians (and maybe a patch set ?)

This would be tremedous. There is some initial (short) documentation at https://github.com/probonopd/MiniDexed/wiki. Be sure to check out especially the "Menu" page, it explains the menu-based operation using the display and a rotary encoder.

I guess it's not possible to connect the LC display with the I2C interface mounted on it's back?

Unfortunately the software doesn't support I2C yet, but you should still be able to use your display by soldering to the connections on the front, I guess (never tried but why shouldn't it work).

[probonopd]

The video has landed:
https://www.youtube.com/watch?v=Z3t94ceMHJo

Thank you very much @mrfloydst 👍

[luisfcorreia]

it's basicly the reason why I'm here

[probonopd]

Also being discussed over at https://news.ycombinator.com/item?id=31062237

[positionhigh]

Hello minidexed friends,

just to keep you updated, the issues with the flash chip on the teensy front is now solved.

https://youtu.be/lwLht-6d_2o

[terracide303]

Would it be possible to add a HID driver so we can load devices that act like a HID keyboard but can be used to add buttons to shortcuts. I am talking about devices for retro gaming and arcade machines like this: https://www.highflow.nl/arcade/u-hid/ultimarc-u-hid-full-featured-version-pcb-with-usb-cable.html?sl=nl. These can also be used to have hardware buttons just over USB. Think that is very handy? You could of course flash anything as a HID device but this was just an example.

[probonopd]

HID keyboards are already supported, but for some MIDI controllers (keyboards) one needs to force USB speed to full with usbspeed=full in cmdline.txt due to #48; and since most HID keyboards don't support that USB speed they won't work in conjunction. So unless this can be solved in Circle, I fear there is not much we can do in MiniDexed.

[172pilot]

Just learned of this project today, and have my amazon cart full of parts to join in the fun! I own an original DX7, so this will be a fun additional sound module for me. I'm curious, and will probably just learn about this once I get my parts together, but if running more than one sound module, is there a way to pan different sounds/channels to different places in the L/R channels or is the whole thing mono like an original DX7? Thanks for all the hard work. Can't wait to start to play with this!!

[Banana71]

Hi 172pilot,

yes, you can set Pan for every Tonegenerator.

• "Pan Stereo panning Can be set graphically from left to right"

Until your parts are delivered you can read something here:
https://github.com/probonopd/MiniDexed/wiki/Menu
The settings are explained under Menu tree

Peter

[172pilot]

Thanks for the reply and link.. That looks great! I can't wait!

[Fetente77]

Hi there, I built the minidexed and it's fantastic. I have, however, a pair of question: why it doesn't save modifies on shutdown? And, is there a way to create my own rom? Thanks all,

[positionhigh]

hi! if you have meant microdexed, please come to our discord chat, https://discord.gg/XCYk5P8GzF
much easier to ask questions and get quick replies.

If you want to save the current state, you have to save it as a performance. you have 99 performance slots.
and by your own rom you mean build it from source ? or with other rom samples ? both can be done, yes. however it is more convinient to load user samples from spi chip.

[Banana71]

Hi Fetente77,
I manage my banks with DEXED and I also edit the patches on the PC.
I create performances directly on the miniDexed and save them as "new performance" on microSD.
https://github.com/probonopd/MiniDexed/wiki/Menu (scroll down to Performance)

[Fetente77]

For positionhigh: I use minidexed for raspberry.

Many thanks for your reply. Now I’ve understood the meaning of performance.ini.
So if I install the dexed plugin, I can create my own syx rom and then import them on my sd?

[vicmertens]

I am starting to build synths an wondered if there is a manual available for the latest version of microdexed touch, with details for the sequencer?

[positionhigh]

It is not a full manual but you can find most information in the WIKI
https://codeberg.org/positionhigh/MicroDexed-touch/wiki/

[viragored]

Hi - Hello from New Zealand.
I've just put together a MiniDexed running on a Raspberry Pi 4, housed in a 3D printed case of your design. Excellent work everyone!
The most amazing thing to me is that one day I was Googling something to do with synths on R Pi, and saw for the first time mention of MiniDexed with the comment that it just works. Less than an hour later I was getting sound out of a R Pi 3 that I borrowed from something else!

And a question:
I don't have much experience of building electronic things and R Pis so would welcome pointers to where I should be looking to get the information for the next step.
I'd like to use a player program on my desktop R Pi 4 to play a midi file to the MiniDexed, and also plug in my Alesis keyboard/controller to play along with the playing midi tune or sequence.
What are the magic ingredients I need to join together a midi file, a suitable player program, USB output from the desktop Pi 4, and USB input into MiniDexed on the other Pi 4? After spending ages in Google, I'm all at sea in terms I don't understand and need to take a break!
I hope someone can provide me with some links to help me.

PS: I've replaced the display in the photo with one that works properly!

[viragored]

A Pico is now loaded with the .uf2 file, hooked up to MiniDexed, all working!! Thanks so much for all the help and guidance.
Now I need to make a bigger box for the MiniDexed. (The project's design (my print is in my picture above) isn't too happy now with all those DuPont connectors, wires, floating boards and jacks and I fear something will get bent, broken or make an unwanted contact and do permanent damage).

[viragored]

With many thanks to everyone for all the help and support, here's a pic of my final (for now) setup.
I've remixed a MiniDexed case on Thingiverse making it big enough to hold the Pi, LCD screen, rotary encoder/switch, DAC and voltage converter, they were a bit of a squeeze in the original case. Also inside now are connections for MIDI in and RCA sockets for audio output from the DAC.
The little box behind the MiniDexed houses a Raspberry Pico with the .uf2 file that makes it a MIDI converter. It's connected to my desktop R Pi by USB, with output through a 3.5mm stereo jack plugged into the MiniDexed. The Alesis keyboard is plugged into the Pi's USB.
Now it's time to learn more about what's going on where and get some proper backing tracks running!

[Banana71]

very nice work, a fully featured miniDexed. I wish I could remove the protective film from the display. 😂

[viragored]

If I catch you taking my protective film off, expect a slap on the hand!
Leaving them on means when they do finally fall off, I've still got a pristine screen underneath. OK, that's not the only way I'm odd...

[Banana71]

everyone has their own quirks:

https://youtu.be/lrjwBvB7APY?si=rNX4lk70xg-cnKe4

[viragored]

[diyelectromusic]

Fingers crossed it'll all work...

Ooo, err... not sure about that. As I say, I've not really looking into it. I hope that won't damage the Pi! Might be worth studying the power section in the datasheet/part schematic to be sure you're happy with what is going on...

It's not really my area but I know USB-C can negotiate power in a much more complex way to previous standards...

Kevin

[Maximo68]

Hi, I wanted to know if there is a tutorial that explains how performances are created.
How do you create a code in .ini format with its parameters?
Is there any particular software?
Thank you.

[Banana71]

Floyd Steinberg once made a video about sound design with the miniDexed
https://youtu.be/KDx8iS59mpQ?si=Njd6GwPQxh5t3PzL

[Maximo68]

Hi Banana71, but how do you create your performances?
Are the banks modified in .sys format or is the code formulated with some software?

[Banana71]

The only thing I use is my miniDexed and Dexed as an editor on the PC + MIDI controller. My patches are only on the PC. With Dexed I can transfer the patches to the miniDexed via MIDI and also edit them directly. I make the performance settings on the miniDexed. When I get the chance, I'll write a short manual or make a video of how I create the patches and performances.

[Maximo68]

Grazie per la risposta. Buon lavoro