Category Archives: instruments

Ratschen Reloaded

This project dates back to 1998, right after I had relocated to Berlin, when Jens Brand approached me about building an interface to control a series of geared motors. These motors were then connected to the axes of a number of ratchets, the general concept being to create very loud, computer-controlled sound, but without employing a speaker system.

© Jens Brand

Ratchets are used in Germany during the carnival season and even a single one can be brutally loud, even outdoors from a distance. So imagine 8 of these in a small room! If I remember correctly he once did a duo concert with a guitar player using a big Marshall stack, and that the latter was not audible anymore when the ratchets where running at full speed.

Back in 1998 there wasn’t a strong maker scene and no distributors like Adafruit or Sparkfun to provide all the control and driver modules that we can choose from now . So the interface was build from scratch, using a Microchip PIC16F84 and discrete MOSFET drivers. The controller didn’t even have sufficient PWM outputs, so it was programmed in Assembler with what I called “synchronous code”. What this meant was that I took note of the execution times of each block of code and added extra NOPs to match them to the PWM frequency. All while polling the serial input for MIDI messages.

Sadly there’s no picture of this initial build and in fact the reason why Jens approached me about making a new version was that the original device had been stolen :(

My go-to microcontroller in 2020 is the Teensy which is build around an ARM processor and programmed thru the Arduino IDE. I like its combination of small form factor, sufficient pin count, and processing power. There’s even a cool Audio Library.

To drive the motors I used some Pololu driver modules, and then all I had to do was to mount all these modules on perfboard and connect them with wires. Not a single discrete component.

The ratchets themselves were also worn down from decades of use, so they needed to be rebuild as well, which was done by our joint friend Paper Blattmacher.

Sadly, the premiere at Phill Niblock’s Experimental Intermedia had to be cancelled (*) due to COVID-19, but I hope we’ll soon have a chance to hear this instrument again.

* actually it was streamed, but that doesn’t convey the physical experience at all

Data violin

For Jon Rose in collaboration with Martin Riches.

This is a MIDI-controlled music robot. While labelled as a violin it is actually a hybrid instrument, with its viola body, but guitar-like frets, and a circular bow as in a hurdy-gurdy.

Martin Riches has been building similar instruments for a long time, but we decided to team up on this one in order to improve upon the control electronics and software design. All solenoids and motors have now continuous control where separate envelopes can be assigned to all elements at a high temporal resolution, allowing for refined articulation.



The Strophonion is a sensor controller devised by Alex Nowitz for manipulating his voice in live-electronic contexts. It was initially developed at STEIM, using their expertise in hardware design as well as their software offerings, in particular LiSa and Junxion.

I got involved starting in 2014, when I helped building the next revision of this controller:


The electronics are largely the same as in the previous version, however we added an option to connect the controllers thru a cable in case the wireless system breaks down. The basestation though is a completeley new design.

Most notable are the 3D-printed shells which were designed and built by chihauccisoilconte. Here’s the new and old designs side by side:


In the following years, Alex and I embarked on a long journey to also update the other half of the instrument design, i.e. the software. The aim was to implement the signal processing in a more open, flexible, and expandable environment, so the complete functionality was transfered to MaxMSP. This process take longer than expected, but in late 2018 Alex was able to present the new version of the Strophonion in a concert as part of his PhD project.