MIdiBox AC Sensorizer

MidiBox AC Sensorizer

My fifth MidiBox (actually the sixth if you consider an older version of the midibox controller - midibox plus) along with the midibox 16e, sequencer, SID, midimerger. In this case the project is the AC SENSORIZER, and it uses distance sensors, like the D-BEAM (Sharp GP2D12) which can send CC messages depending of the distance of an hand above them.
Besides this, it would be possible to use every kind of sensor which could provide an output from 0 and 5 V (even one between 2 and 4.2V, for example, will work!). This permit for example to build ribbon controller, XY pads, breath controller... these extension are actually being studied! ;-)

I recorded two video using this box: the first using Midibox ACSensorizer with a solo violin of Garritan Personal Orchestra, the second using a custom made ribbon controller (see below)


Ribbon controller

The ribbon controller is a sort of "strip" on which you move your finger, generating a CC message depending on the position of your finger on the ribbon. This is used for example by Jordan Rudess of Dream Theater.
For the construction of my ribbon controller i was inspired by some project found on the net
I started by cutting the tape of a VHS (not a SVHS as said by someone): the tape has a resistance of the order of 100KOhm, depending on its length. Remeber to test the resistance of the tape before cutting it and on the BACKSIDE. A lot of VHS i had were not conductive...

ribbon_controller(0)_t (10K)

The tape was glued on a plastic stand, which later will be placed on my keyboard.

ribbon_controller(1)_t (9K)

On the tape i layered a metal guitar string. The trick is that the string should NOT touch the tape unless you press on it with your finger. when you press, you generate a resistance that depends on the position, thus achieving a sort of linear potentiometer.
In order to fix the string i used two little breadboard pieces, and i soldered the string on them, using also a small wire in order to make, later, the electrical connection.

ribbon_controller(2)_t (8K) ribbon_controller(3)_t (6K)

Contacting the tape was the most tricky thing. I made a sort of "sandwich" with the tape, an electrical wire (for the contact) and an conductive aluminum foil (the one used for food). The tape, thw wire and the foil were layered several times one between the other, and then tightnened with insulating tape.

ribbon_controller(4)_t (8K) ribbon_controller(4)_t (6K)

As you can see, the string doesnt touch the tape, unless you press it down with your finger!

ribbon_controller(5)_t (4K)

At the end, you have a sort of potentiometer: you have to connect the two tape edge to 0 and 5V and the string to the midibox input, for the signal

ribbon_controller(7)_t (8K) ribbon_controller(8)_t (6K)
Important: in order to avoid flickering at minimum value when the string is not touched, i added a cap between ground and the string itself.


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