AXiS-49 teardown


We touched on harmonic table MIDI controllers when [aris] was building one. [Ken Rushton] has one of C-Thru’s commercial keypads, the AXiS-49, and disassembled the device to show how it works. A PIC18F2450 microcontroller provides the USB interface and is connected to a dsPIC33FJ128GP310 digital signal controller which decodes the keypresses. The membrane buttons are made with two concentric graphite disks that touch gold contacts. The microcontroller measures the time between the two points contacting to determine the button velocity. monome button clones also use circular contact pads, but cannot calculate velocity because they only have one element.

[via Matrixsynth]

Harmonic keyboard controller


[aris] is continuing work on his harmonic table keyboard midi controller. Instead of the traditional linear keyboard layout, keys are laid out in a hexagonal pattern. This is the same idea as the C-Thru AXiS, which you can find a video demo of here. Along the left edge is a row of buttons to transpose the layout up or down. Switches for octave up and down along with a generic slider are also included. The final controller will include a 16×2 LCD character display. The core of the controller is MIDIBox, and he’s using the SDK to write the custom C code. Embedded below is the first test with just four buttons wired.

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