building midi control (max number of buttons, knobs, sliders

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mikewww
 
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building midi control (max number of buttons, knobs, sliders

Post by mikewww »

I was looking at buying the Arduino Leonardo to build a custom midi controller but I want to have a total of

136 buttons (4x32 grid and 8 separate buttons)
32 faders
16 knobs
2 touch strips

I know it says you can connect up to 8 of the grid boards together but can I add buttons else where

would that be possible?
is there a max number of button, knobs, etc you can have?

Thank you for your help

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pburgess
 
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Joined: Sun Oct 26, 2008 2:29 am

Re: building midi control (max number of buttons, knobs, sli

Post by pburgess »

The Trellis grids use I2C, so they only need 2 pins (SDA and SCL...if using an Arduino Leonardo, these are also digital pins 2 and 3, so those aren't available for other purposes). I think that leaves 8 digital inputs and 6 analog inputs available.

One way to get more analog inputs is to use a separate analog-to-digital converter, such as the MCP3008 in the shop (adds 8 10-bit analog inputs, but requires 4 digital pins) or ADS1015 (4 12-bit inputs, uses same 2 I2C pins as the Trellis). I'd need to read up on the former, but it can probably be cascaded or use a chip-select pin to allow using several.

A different route would be to switch to a board like the Teensy 3.1, which can have up to 21 analog inputs, and the usbMIDI library was written by PJRC specifically for these boards.

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