Open PAD (aka akai MPD style PADs on MIOS)

[Phatline]

Hi, i recently buyed a Akai MPD226... i hoped i could use it standalone with MIDI-TRS/DIN Hardware... but LED Feedback doesnt work (aka Notes from a Hardware Sequencer give no Response to the PADS)

- short the Akai Firmware sucks.

I made a teardown, searched on the MPC-Stuff website... and made PAD-Footprints for KICAD, made shematic and so on:

 

 

Result: OpenPAD

 

I dont use the same shematic as Akai did... the multiplexed 4 Inputs of a STM32F103 with some HC595. My goal is to use 2x MCP3208 and connect them without switching to the PADs.

SO I HAVE A QUESTION:

the akai Resistive Foil - has a resistance from 280 Ohm if you measure diagonal between the corners.

Our MCP3208 wants 0-5V.

How do i limit the current going thru the Foil, without reducing the 0-5V Range?

OP-Amps? how? Thx 4 Input

 

I too have drawn a Core PCB 4 Pick and Place... incl STM32F407VGT6 ;)

 

 

Edited January 3, 2023 by Phatline

[Phatline]

the quest still is:

the akai Resistive Foil - has a resistance from 280 Ohm if you measure diagonal between the corners.

Our MCP3208 wants 0-5V.

How do i limit the current going thru the Foil, without reducing the 0-5V Range?

OP-Amps? how? Thx 4 Input