#1

I’m a big fan of Teletype and the I2C protocol. Lately, I have been experimenting with the idea of using I2C to control external devices outside of the Eurorack case.
Here’s a little prototype module that I’ve built – and which I would like to share with you.

There are two reasons for me to post it here on lines:

First – Maybe someone else finds this module helpful and would like to build it or modify it. The schematic, BOM, firmware code and more details are all in the Github Repo.

Second – I am definitely no expert in electronics nor circuitry design … But I’m sure some of you here in this great community are! So I’m very much looking for input on how to improve it or even correct some mistakes I made. Ideas, recommendations and tips are greatly appreciated and I am happy about everyone who wants to contribute.

Thanks!

i2c2midi

i2c2midi is a simple DIY 3 hp eurorack module that speaks I2C and MIDI. It’s primarily build to be used together with monome Teletype. It receives I2C messages from Teletype and converts them to either MIDI notes or MIDI CC messages to control external devices like synths and effects.

Currently in prototype status: The first prototype was built using a horizontal protoboard and a LEGO 2x16 plate as front panel.

Todo: Create a PCB and proper front panel.

i2c2midi_diagram
i2c2midi_diagram1680×728 15.5 KB

Details

  • DIY eurorack module (prototype)
  • 3 hp (LEGO front panel)
  • Inputs: I2C
  • Outputs: 1 x MIDI TRS (Type A)
  • Based on Teensy 3.2

i2c2midi_top
i2c2midi_top1800×1200 292 KB

i2c2midi_side
i2c2midi_side1800×1200 166 KB

Usage

The firmware is written specifically for I2C messages sent from Teletype using the disting Ex MIDI OPs by scanner-darkly. The module “poses” as a second disting.

Send MIDI notes

EX 2
EX.M.CH channel
EX.M.N note velocity

Send MIDI CCs

EX 2 
EX.M.CH channel
EX.M.N controller value

Note off messages

The firmware takes care of Note off messages automatically, but is currently monophonic per channel. Note off messages are sent when a new Note on message arrives or after 500 ms.

Todo: Make the note duration of 500 ms editable via I2C as well.
Todo: Make it handle polyphony.

Example

I am using the module together with a MIDI splitter, having Elektron Analog Four on channels 1-4, Nord Lead on channels 5-8, and OTO Bim and Bam on channels 15 and 16.
Here’s an example patch, sending MIDI notes and CCs to Elektron Analog Four and Nord Lead from Teletype: https://www.instagram.com/p/CKH3Jq5KxIk/
The main script is:

EX 2                     // following code is for the "second" disting
EX.M.CH + 1 * 4 TOSS     // select A4 or Nord Lead randomly
EX.M.N PN.NEXT 0 127     // send a note
EX.M.CH 5                // select Nord Lead
EX.M.CC 74 RRND 50 127   // control Filter Frequency via CC

Github Repo

34 Likes
#2

This is awesome, would be excited to use this with teletype.

1 Like
#3

I’ve been following your posts on IG for awhile with this and am super fascinated! I don’t have a lot to contribute at this stage unfortunately but I am super looking forward to seeing how this works out! Great work as always!

1 Like
#4

Amazing! Congratulations! Is there any chance you commercialize this module in the future?

1 Like
#5

Awesome info. A quick question - I use Ansible a lot. If Ansible is connected to Teletype could I get Kria / Meadowphysics / Earthsea to output midi using this?

1 Like
#6

yep, since it uses the disting ops you can use the existing disting modes 3 (all notes sent on MIDI channel 1) and 4 (notes are sent on MIDI channels 1-4).

4 Likes
#7

Thanks @Whatwetalkabout! The build is very very easy – I can only encourage you to build one for yourself :slight_smile:

#8

Thank you @SMesquida. Glad to hear you like it.
I probably won’t be able to commercialize it … but I would like to make it a more “professional” DIY module.

There are three main things I would like to develop further and need help for:

  • Create a proper PCB
  • Create a proper front panel
  • Add polyphony per channel to the firmware
2 Likes