AudAVR (or Arduino for musicians)

[mrkva]

AudAVR (codename)

Dear friends,

I would like to share a project idea I have for some time (and probably has been thought of by many of you as well) with you - and hear your responses, comments and criticism!

Little about me - my name is Jonas and I love modular synthesizers (obviously). I works as a performer/artist and study in Netherlands at Institute of Sonology. I am not engineer, but I love working as one for interesting projects. I programmed and designed circuits for bunch of artistic installations with Arduino code, but I also work in C, Supercollider, MaxMSP and others, most recently trying to figure out Asembly code. Here is my web for those interested: http://mrkva.ovecka.be

Idea of the project is to create universal and open design for utilizing AVR microcontrollers as various modular synth modules. One could say, "Arduino for musicians" - AVR controllers with combination of Arduino platform offers quite interesting possibilities for our musical purposes. By using DDS (Direct Digital Synthesis from filtered PWM signal as low cost option) or dedicated DAC chip with combination of 32kb of Atmega328 chip we are confronted with a lot of space to experiment and play.

After designing the board, the plan is to start designing our own musical software, which can be than easily transferred via USB right to the board. If one would get bored with his module, he/she could easily rearrange functions of pots/outputs/inputs (basically the whole module) by uploading new program to the chip.

Wiki with all the schematics, PCBs and codes will be available and open for collaboration. One of the ideas is to create a little code snippets which would allow you to combine your own module with ease. And by combining bunch of modules - create our own instrument.

There is no financial gain planned on this project - everything will be licensed with GNU/GPL and free for download. There will be possibly some professionally made available PCBs after prototyping, sold for the cost of the board + postage.
Main rules are to keep everything simple, open and as SMD-component-free as possible (so - easy to assemble).

Planned 'example' specs of low cost (DDS) module:
4 potentiometer / sensor inputs

2 'audio' inputs
2 trigger inputs

4 'audio' / cv / trigger outputs

2-digit display
4 RGB LEDs

The better-config module would have external 12-bit DAC chip, multiplexers (therefore more I/O) and possibly matrix display.

Possible uses I can think of (some I've even tried with Arduino): easy sensor-to-CV convertor (light, pressure, temperature, whatever you can think of!), random trigger generator, advanced tap-tempo, envelope generator, strange oscillator (gendy anyone?), random CV generator, weird LFO with all kinds of shapes and many more (waiting to be discovered by you!)

Since the whole project is open, I am now inviting you all to collaborate and discuss. Currently I am designing the schematic for the first low cost prototype (and waiting for the DAC chips for other prototype to arrive) - so if you feel like it, send me a PM, I can send you the Eagle files. Later on, I will make a wiki for this project and make the collaboration a bit easier.

Thank you for reading!

[mosc]

Jonas, this sounds like a great project. I'm personally not too familiar with Arduino programming; I wonder if it would be possible to build VCOs and filter modules.

Anyway, if your project takes off, or even before it does, you are welcome to have a dedicated sub forum here on electro-music.com to help with member communications. Sometimes, a WIKI isn't enough.

Anyway, I wish you the best of luck, and keep us informed.

[mosc]

At another member's request, we have created a new Arduino sub-forum in the DIY section. I have taken the liberty of moving this topic to there.

[MusicMan11712]

Cool! Thanks for setting up the subforum. I have been thinking about playing some more this summer with my arduino. So this forum should inspire me!!

There are a number of posts in various places here at electro-music.com. Perhaps I will post links to some of there here so they are easier to be found.

I read a little about programming the AVR directly last summer, but that is way beyond my present abilities. I seem to recall seeing a circuit somewhere (perhaps arduino playground) for getting different waveforms from the Arduino's pulse waves. It sounds like there's lots of potential.

Looking forward to seeing what others are doing here!!

Steve

PS: I just looked this one up, so thought I'd post the link.

http://arduino.cc/en/Tutorial/SecretsOfArduinoPWM

[emeb]

Sounds like a great project. Just wondering how this is different from the Ardcore?

http://20objects.com/ardcore/

There's also a Euro-format version:

http://www.analoguehaven.com/snazzyfx/ardcore/

[mrkva]

[v-un-v]

[cappy2112]

[quote="mrkva"]AudAVR (codename)

Dear friends,

[mrkva]

[quote="cappy2112"]

[mrkva]

Hey guys,

so here is what I designed so far: http://f.cl.ly/items/1j2Y1F3Z473v0y0u1I23/audavr_0.1.1.png
(too big to be displayed here)

few comments:
* not sure about 5V input for microcontroller - here I am using lm7805 to reduce the input 12V but that is not cool, since it can get hot and it is basically wasting energy. i know there are some modular power supplies which can deliver 5V, but how common is it? what do you guys think?
* still need to design trigger inputs - any ideas for good debouncing?
* still need to design rgb LED circuitry (not sure if i shouldn't skip that to keep it lowcost)
* still need to design 2 digit display circuitry - any tips for good multiplexer? before i used one dedicated for 7-segment displays, but maybe it could be handy to use something which can display other things than numbers

All comments welcome! If anyone feels like contributing, I can send the eagle files no problem
Have a nice day!
Jonas

Edit: Whops I already see a mistake at potentiometer header! Please tell me if you see some others!

[cappy2112]

[mrkva]

[cappy2112]

[mrkva]

[mrkva]

Hello,

I am finishing first prototype. What do you guys think?

http://cl.ly/MGBl

Jonas

[elmegil]

I'm not sure I understand the analog input section, particularly the arrangement of the pots. And the zeners on D101 through 104 inputs, shouldn't they have some kind of current limiting on them?

I like the use of the 4922, I've actually been using those for some of my own Arduino projects lately.

[mrkva]

[elmegil]

Looks nice.... so do you plan for this to be its own standalone board, rather than a shield or something?

[mrkva]