The Electronic Jug Band Exhibit at Maker Faire Rome 2023

This exhibit at Maker Faire Rome 2023 is all about making unconventional MIDI controllers for Electronic Music!

Link to the Maker Faire project information: The Electronic Jug Band.

The primary instrument is the EMMMA-K which is an Open Source project published on Github here EMMMA-K-V3-M but there are others with examples shown in the photo below.

There will also be a first look at a new instrument called the EMMMA-U which based on the ukulele and under development. It can also be configured to be any other 4 string instrument with examples being bass guitar and mandolin. There is a photo below and more information to follow after the Maker Faire...

History of the EMMMA-K v3

I have made two previous versions of the EMMMA-K and felt that I was close to having something useful with the second one but it wasn’t easy to build and the touch pins weren’t that great so it certainly wasn’t worth making any more of them.

At the beginning of 2023 I decided to have another go at it and see if I could come up with something that performed better and was easier to reproduce with the goal of actually being able to make one for someone who was interesting in trying it.

The first thing that I discovered is that the microcontroller boards that I was using (Teensy LC) had become unobtainium thanks to the global semiconductor shortage. That was a major setback because I had found that the Teensy had by far the best performing hardware to implement touch pins with the required sensitivity and low enough latency for music applications.

I had tried the ESP32 before with some success although I wasn’t really happy with it for this application.

After quite a bit of research including trying some boards with the ATSAMD21 microcontroller I discovered that there were two relatively new versions of the ESP32 (the ESP32-S2 and ESP32-S3) and when I started digging through the documentation I found that both of those had what the manufacturer Espressif calls “Version 2" of the internal touchpin hardware plus they both have 14 pins that are touch capable compared to the Teensy’s 11.

I purchased some dev boards for both the S2 and S3 versions and found the performance to be amazing which is great but what I find strange is that Espressif hasn’t promoted these improvments that they made so I believe that it has been largely undiscovered!

Having found a good solution for touchpins I decided on the following design improvements:

- Create printed circuit boards (PCBs) to facilitate connecting the touchpins to the microcontrollers which reduces the tedious hand wiring and makes the performance more consistent and reproducible.
- Use additional touch pins and an OLED display to implement the user interface.
- Improve the ergonomics of the touchpins themselves.
- Improve the 3D printed enclosure to make it more durable and comfortable to use.
- Come up with a low latency wireless solution to make the device truly portable.
- Find a better solution for tilt measurement to provide pitch bend, mod wheel, note volume and potentially other MIDI controller capabilities.
- Add a chord generation capability
- Add a rocket sticker to the case :-)

As of September 2023 there are 3 of these in existence. It takes a couple of days to build one which is much improved from before and I’ve found that they all perform exactly the same which is one of the goals as mentioned above. The total cost of the electronic components is around $50 Canadian and all are readily available.