Monstrous Casio Keyboard

Circuit Bend Project

Commission Specifications

Commissioned by Hannes Pasqualini from Papernoise

Modify a Casio VL-tone to include:

• A low pass filter

• Two audio oscillators, with patch bay

• Voltage starve

• As many circuit bends as possible

• Mounted in a customised wooden case

Selecting a box

I had a selection of boxes in my workshop, luckily I managed to find the exact size box that didn’t need many modifications.

Top Panel Demo

A wooden insert panel was made using ply wood and cut to size with a disc saw. The knobs were used to keep a scale of perspective. The gap around the edge of the keyboard is 1mm.

PATCH BAY

MOD 1

MOD 2

CIRCUIT BEND 1-11

POWER

AUDIO OUT

ON/OFFRESET

PITCH 1 &2MOD 1PITCH MOD 2 PITCH

1&2

Panel Demo Design

I made a quick sketch using word to show how the insert panel would look.

Panel Design

OSCILLATOR A

MODULATION

PITCH A Pitch B RESET

OSCILLATOR B PITCH

POWER

FEEDBACKOSCILATOR BOSCILATOR A L.P.F.

FREQUENCY

OSCILLATOR A

PITCH

STUTTER FOLLOWER BASS FOLLOWER

OSCILLATOR A

OSCILLATOR B

BASS STUTTER

The panel design was finalised in power point, the page size was set to the same size as the panel. The file was converted to 16-bit BMP format with the colours inverted. This is so that the file is compatible with the marker laser.

Box Logo

This is the Paper Noise logo. However, I forgot to invert the colours, which meant that I had to make a new plywood panel and re-etch the surface.

Laser Etched Panels

Populated Panel

Oscillator Circuit Diagrams

I used two oscillators on this keyboard. The first was a Hex Schmitt Inverter Oscillator and the second was a stepped tone generator (atari punk console). Below are the two circuit diagrams I used.

Low PAss Filter Schematic

The low pass filter is a passive design, this means it doesn’t need any power to operate, the drawback to this design is that it reduces the output signal by a noticeable amount.

The resistor used was a 10K potentiometer, so the frequency could be adjusted.

Wiring Up

Completed Box

Completed Casio

Casio Video

Online Projects

• http://www.youtube.com/user/circitfied?feature=mhee

• http://soundcloud.com/circitfied