Chimaera

Case

This is the case design for the Chimaera - a poly-magneto-phonic theremin. It is a dynamic design based on configurable script parameters.

Chimaera-S144 case with simple line engraving.

Chimaera-S144 case with neutral line engravings.

Chimaera-S144 case with piano key engravings.

Chimaera-S144 case with piano key engravings and standard paint job.

Chimaera-S144 case with piano key engravings and alternative 6:6 paint job.

The enclosure was designed with different playing styles in mind: it can be put flat on a table like a keyboard, strapped around like a guitar or used standing upright like a cello. As the instrument is played with the hands and fingers, we wanted to have an agreeable touch, which lead us immediately to wooden materials. Thin (2-3 mm) air-plywood is the material of our choice. It can easily been laser-cut. We use a base rip construction in which the printed circuit boards and cable connections are embedded. The rip construction then is wrapped with a kerf-bent plywood sheet. This gives us a robust, ultra-light construction with rounded edges ready to be rocked on.

The case is engraved with short reference lines (each 5 mm) to represent the underlying sensors (they are right below the markings). Additionally there are longer reference lines after 3 sensors each corresponding roughly to the width of a standard piano key (15 mm). As this is a continuous music controller, the lines per se have no meaning, they are meant to help orienting on the virtual continuous string. Their meaning is dependent on the musical mapping of the software/hardware you steer with the Chimaera.

Above there are different schematics of the wrapping plywood sheet for a device with 9 sensor units (144 sensors). If we configure our software synthesizer to map the continuous range to 4 octaves (4*12=48 half-tones), the long lines represent a standard keyboard layout (144/3=48 half-tones). But we may want to map our range to 8 octaves, 1 octave or 1 note only. It therefore makes not always sense to paint a standard piano key layout onto the device, it would only suit one given configuration and interfere with many others. We want the user to decide what the lines mean in their specific setup, the advanced player may ignore them altogether and play solely with the help of hearing and muscle memory.

We have therefore come up with different styles of engravings and paint jobs to accustom different needs of players.

The case design consists of a couple of ECMA scripts for QCAD. The script assembly is adaptable with an overseeable amount of variables, the most important ones being: number of sensor units, material thickness, material tolerance, bolt and nut dimensions.

There is a Makefile to create static *.dxf, *.svg and *.pdf design outputs for a laser cutter.