The pads have arrived! + more photos

A project log for DIY USB MIDI controller MPC style

An MPC style MIDI controller featuring a 4x4 FSR matrix and based on Teensy 3.0, fully compatible with the Teensy Audio Adaptor Board

Michele PerlaMichele Perla 08/19/2014 at 23:141 Comment

Hello there,

The used Akai MPC 2000 pads arrived this morning, yay!

I took the opportunity to share with you actual dimensions of the pads, as well as some photos of the inner guts of this prototype; let's start with the description of the electronics photos:

16 channel mux breakout board pin connector

This is the mux breakout board connector; beside the blue wires mess, which is composed of the FSRs leads, you can see in order from left to right, and color coded:

Vss (ground)- Vdd (5 V) - A - B - C - D - Common Out - Inhibit 

This board is plugged in a breadboard and connected to the Teensy using some jumpers:

Inside the prototype 2

You can see that apart from the red jumper for the ground connection, everything follows the same color coding as on the breakout board:

RED for Power - YELLOW for A-B-C-D - GREEN for Common Out - WHITE for Inhibit

A-B-C-D are connected to pins 9-10-11-12, Inhibit to pin 8, Common Out to A0-pin 14 and grounded through a 10 Kohm resistor. You can see that the electronics and the connections are really straightforward.

Now for the dimensions:

- Top layer: 

. Pad width : 1,1875 inches

. Spacer between pads : 0,1875 inches

These could be approximated to 1,25 inches and 0.125 inches and will be useful later when designing the final enclosure (e.g. to cut an acrylic sheet with some holes to be put on top of the pads to keep them together with the structure, which will also make the thing look sleek ;D )

- Bottom layer:

. Pad width : 1,25 inches

. Spacer between pads : 0,25 inches

. "Pressure" circle diameter : 1 inches

For "pressure" circle I mean the little convex circles under each pad, which will be covered with Velostat;

The width and the spacer reflects the approximated top pad dimensions; these are necessary to design the PCB pads.

I made some math, and the first thing that comes out is that I cannot fit 16 pads in a single PCB, at least not in Eagle CAD; the maximum available area in the free version is 100 mm * 80 mm ( 4 inches * 3,2 inches ), therefore I have to either stick with 4 boards with 2x2 pads each ( 3 * 3 inches ), or design these with another tool.

You can find more pictures in the Google Drive shared project folder link.

See you next time with the PCB layout of the pads, and who knows what else! 

Stay tuned,



Ed wrote 08/25/2014 at 15:50 point
Hi Mick,

I registered to follow this project only. Looks like your pads are really responsive, unlike on real AKAI controllers.

Good luck, i´ll follow your steps closely ;)

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