This project now exists. Github link for more info.
Old post june 2020:
Short version :*
The idea is to have a Raspberry Pi Zero W hidden in the Eurorack case, and powered by the case. It would receive OSC sent from various devices and transmit the messages to the ER-301 via the i2c bus using the ii protocol. Do you think it’s technically possible ? What is required on the software side ?
Long version :
There are now many ways to control the ER-301 in addition to the CV inputs present on the module. For example, from Norns via Crow and I2c, or Teletype via I2c (and now Teletype receives MIDI too and can convert Midi messages to I2c thanks to @scanner_darkly )
I’m thinking of something else, in addition to all these possibilities, but I don’t know, mostly on the software side, what it would take to make it work:
The idea is to have a Raspberry Pi Zero W hidden in the Eurorack case and powered by the euro case (power consumption is probably < 200ma ). It would receive OSC and transmit this to the ER-301 via its I2c port.
Is it technically possible ? The power consumption of this small Pi is really low so it could be powered by the 5v bus of most euro cases (or the two 5v pins available in the Intellijel cases) and thus not require another power source/cable. I hate to have 4 or 5 cables coming from outside of the case. It is unclear yet if I can connect the Pi to the 301 directly or if I need to create an additional circuit including a level shifter and pull-up resistor (and 5v power protection for the Pi)
Now, how does the RPi speaks (ii) and sends SC.CV SC.TR etc ? That’s a question I’ve always asked to myself. When I designed my Norns clone I put an I2c output (routed the gnd scl and sda to a header) but didn’t go further, so this output is useless haha. If it was a Teensy I could borrow some code from the Telex projects but the Teensy doesn’t receive WiFi… Edit: just found out the ESP8266 module that adds wifi to Arduino, that’s another possibility im considering then
Do you think I should use a Python program for that ? I’ve already found a Python-Osc library, it might be helpful.I’m not familiar with Python but I can learn.
I’m not saying that OSC would be ultra reliable for sequencing without latency but for controlling dozens of parameters from Lemur it might be just fine.
Other options I thought of, always using a RPI zero are: plugging the Pi zero to Teletype, using PureData to convert OSC to Midi and then TT could convert this again to send messages via ii to the 301. Probably too much power required by the RPI to be powered from TT though.
Installing Norns on the Pi Zero, connect to Crow ? Even if Norns could run on this small Pi, same thing it would need an additional cable to power the Pi. Loads of USB cables around the modular I’m not a fan of that. But using the Norns system would be useful yes since it already speaks OSC, talks to Crow etc…
Please let me know if you know have an idea on how to make this work, or you’ve already tried implementing such a thing…
P.S: I’ve mentioned Lemur but it could be any OSC speaking devices and since this setup would use a RPI, why not Midi Ble too? (Using a Roli control block to trigger the pedal loopers of the 301…) Obviously the SC has been made to be used with CV but sometimes when there are a lot of parameters to control, some « Wireless » faders could be handy