DIY Midi Controller w/ Multiplexer

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Hi there!

I'm looking to take an old organ from the 70s and use the existing keys to output MIDI to a computer.

It's been quite a few years since I last used an Arduino and I am looking for help finding the necessary parts.

For right now, all I need to do is make a simple circuit: Power goes to the "bus bar", a key is pressed, the circuit is completed, the signal is sent to the board, and a note plays on the computer.

circuit (4)
circuit (4)620×260 5.22 KB

I counted 157 keys, not including sliding pots, buttons, etc---Well over the 127-note limit for MIDI, and definitely more than the 7 pins on an Arduino Pro Micro.

Where can I get started?

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Since you sound somewhat experienced, I will toss out a few clues: debounce/bounce library for the keys (see basic examples in IDE) and a multiplexor so you only use 1 Arduino DIGITAL pin.
Also, fix your wiring diagram; you have a direct short from 5v to G- lots of smoke!

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Hello :waving_hand:, I am working on a very similar project myself, converting an old CONN organ to MIDI and connected to a synthesizer. I made up this board for multiplexing all the inputs from the organ into an Arduino. The boards can daisey-chain together, up to 256 inputs. I purchased extra boards, so I could give you some boards to help you with your project. If you are interested I can help you with more details about how I am doing the wiring, etc and software for the midi controller

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Here's the link to the boards on Tindie https://www.tindie.com/products/flow_state/multiplexer-screw-terminal-16-input-io-board/

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