GEP Contraption

Categories: Software Prototypes/Non-Commercial Products

Submitted by:Matias Homar

24 May 2023

Elevator Pitch

GEP Contraption

GEP Contraption is a MIDI controller/synthesizer that enables people without any experience in music to create and manipulate sounds by bodily motions.

Product Description

GEP Contraption

This controller/synthesizer is built with the intention to serve as an artistic and pedagogical tool. It allows the use of the body to create and manipulate sounds by configuring motion sensors as triggers from the moving body in front of them. The sensors are used as separate modules that can be assign to any MIDI CC within a software (Ableton, Reason, Reaper, etc.). At the same time, it can work as a MIDI synthesizer by sending note on and off messages. GEP Contraption is meant to be replicable by any person that can access the code. In this way, it can be adapted to the necessities of whom intends to use it. The current version consists of 12 motion sensors that are grouped into 6 different units. Each unit is assigned as a MIDI note on/off message or as CC messages.

How It's Innovative

The device allows the use of any type of motion in front of the devices in order to create and manipulate music. It can be used as an instrument, as an art installation object and as a pedagogical tool. Its malleability permits to adapt the instrument's layout to accommodate the particularities of its users. The use of motion sensors (ultrasonic sensors) makes it reliable under any environmental circumstances. GEP Contraption has been tested under different situations and by people with different abilities (trained musicians, dancers, children, people with Parkinson and mobility issues). Through these experiences it was possible to develop its current layout that allows a comprehensive and intuitive use of the instrument. From an initial state of exploration to a more advanced use of the instrument, people using it will create music instantaneously that will only depend on the selection of the sound source (whether an acoustic/electric instrument or a Virtual Instrument). As it was mentioned before, GEP Contraption can be used as a virtual instrument or virtual controller. Simply put, it can be a touchless keyboard or an effect controller by motion.

See MIDI Innovation In Action

Most Inspiring Use Cases

GEP Contraption has been used as part of many performances with dancers and musicians. The fact that it reacts to the motions of dancers has given it a compelling approach on how to create a full performance. Also, working with kids it can show how significant it is to feel the act of creating music with the body. Watching the reaction of people once they feel that their motions triggers and manipulates sounds is an inspiring act by itself.

Expansion Plans

In the future it will take the form of multiple modules that can be used separate or together. In essence, the expansion will take the form of a GEP Contraption 360. This will imply the use of the same 12 sensors times 4 giving a surrounding device that can be positioned in a way that will embrace the performer/s.


At this moment there are no plans to commercialize the product. It was born as part of a bigger project based on open software and hardware. One of the main purposes is to be used by schools given its open source nature and the inexpensive cost. The device can be built with and Arduino Uno or an ESP32 microcontrollers.