#5 - The Licences

A project log for MAD - Modular Audio Devices

A set of Eurorack modules to control synths, make custom MIDI-compatible interfaces and USB audio, powered by Teensy 3.6

Michele PerlaMichele Perla 05/01/2017 at 13:590 Comments

MATT is going to be a commercial project.

My goal is to make a crowdfunding out of this and try to earn a living by producing MATT and future modules for it.

Schematics and PCB layouts of main modules

Some parts of MATT's hardware will be delicate and will require careful PCB layout considerations, and to make my design easier through all the different supplies involved as well as to reduce noise in the analog domain due to interferences from digital traces, I will probably use more than 8 layers PCBs, which is not exactly affordable for everyone anyways. So I am thinking of not releasing the layouts, at least of the CORE.

But I would release the schematics for reference, for anyone to hack around it.


I am also thinking of releasing the binary for the Xilinx CPLD, but not the source of the VHDL. This may change in the future; also, for all the VHDL/Verilog hackers out there, a programming header will most probably be present on the final IOAPEX module, so if you want to upload your own code feel free :)


All the code to drive all functionalities will be open source. Open sourcing the code is a must in order to give back something to the Teensy community, but also to enable users to develop all kinds of custom submodules.

Submodules: the real deal

I would like to keep the focus of users on the creation of new submodules, which are the real key element of this project.

The base specs for modules, as well as barebones versions of modules, will be fully open source and open hardware.

The analog IO modules could be made easily by using perfboard; eg. a JFET buffer for a guitar. I will use standard 0.1 inch headers wherever possible, and I will try to keep their spacing in 0.1 inch multiples. As long as the max. output value of the module respects the specs of the CORE onboard input module, anything goes.

Same thing for the IOAPEX modules: the IOAPEX is in fact designed specifically to keep the external components to a minimum. As already explained, each type of sensor will require only 1 mux, and maybe a couple of passives. I will release base layouts for digital in only modules, digital out only modules, and analog in only modules.

I was also thinking of making the easiest module, that is one module with one mux, a jumper to select its operation (analog, digital in, digital out), and then 16 plated thru holes to connect to anything an user would like to.

Let's not forget that every submodule could be used with ANYTHING else, really. In the end these will just be muxes and switches. You want a simple button matrix to use with your Arduino? Get the first mulitplexer example sketch you can find online and plug your arduino to the module through its provided pin header and voilà


Some of MATT's design files will not be open, I know, but its key part will be fully open, giving the users simpler ways and tools to make custom and powerful audio solutions.