Midi Harp

- metallic strings as touch sensors
- midi note sent when the string is released
- release time -> note velocity

- auto-mute when a lot of strings are touched
- metallic table for percussive sounds or mute
- optional control change or note on touch

- multiplexer for more strings
- simple pedalboard to simulate the chromatic harp


same behaviour as the midi harp

- long switches send notes when they are released

Hurdy Gurdy

- drawing pins or metal rectangles as keys
- motor / dynamo as a wheel -> analog input
- the keys could be glued to some rubber band to better the feeling

- polyphonic capabilities as an option
- different midi channels for each string

Midi Surface

- each touch key and led on the same pin
- piano keys mapping
- slider mode :
- beginning on first or last key gives a full range CC
- touching a single key gives the absolute value
- sliding it in the middle, "smartphone like", makes a relative change to value

- menu key which gives access to the midi settings, channels, controllers, notes etc. for each key
- each key is a sub-menu, whose name is written on top of it
- the leds show the current preset, blink / move on edit

- keys pressure to some cc ? aftetouch for piano
- experimental velocity detection from touch speed

Midified piano

- very small magnets put vertically on each key front
- magnetic switches or hall sensors for each
- all the sensors can be put together on a thin bar, easy to carry and install

- the hall sensors should give enough data to detect velocity ( keypress time )
- multiplexer for more keys

Optical Passive Mixer

* mono channel

- one photoresistor
- second photoresistor on the same light source for balanced operation

* for stereo mixing, use two mono channels from the same mono input

`Arduino controlled`

- with software slow pwm to control 6v bulbs ( one for each mono channel )
- midi implementation


`Screen controlled`

- simple Processing app for computers and android, that transforms cc values in squares of light
- values from touch GUI, keys, midi input or file


audio in ------ :::: ------ audio out

light square
on a screen



-----------------[:::]------- left + ----->
| (left bulb)
| ---------[:::]------- left - ----->
| |

in + in - to passive summing

| |
| ---------[:::]------- right - ---->
| (right bulb)
-----------------[:::]------- right + ---->

The simpliest version could be : Volumizer
Add Volume and Pan to any signal, thanks to 3 tactile switches and leds, memory preset and midi input

Shiny Click Box

Add metronome and midi outputs to everything with has screen :

- photoresistor putted on the screen as a detector ( with a black small enclosure to avoid light from behind )

- Trig by a simple video file with quality audio and metronome flashes encoded on the video stream,
or an application to play audio on headphones and a synchronized midifile on screen

- multiple resistors can be routed to multiple click tracks, or send midi events
- variable luminosity can be used to send control changes

With Arduino and photoresistors, or maybe just with a simple transistor oscillator powewered by the photoresistor, and some control (volume, pitch, audio in jack to mix with the click sound)

Gnu Ideas



open source
& custom devices
by matthieu metzger