Copyright (c) 2018 Matthieu Metzger

  "Systole's Gnu Ideas" are free ideas.
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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

         or

 `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

 
  MONO UNBALANCED WITH SCREEN
  ***************************

        audio in ------ :::: ------ audio out                        
                       ______ 
                      |______|
                      |______| 

                    light square
                     on a screen



  BALANCED CHANNEL, VOLUME, AND PAN, WITH ARDUINO
  ***********************************************

                     photoresistor
                          v

       -----------------[:::]------- 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)