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Topic: 61 key midi controller with 64 inputs (Read 3408 times) previous topic - next topic

marsbuilt

Hi, I am hoping I could get some advice on where to start with this project. I would like to build a 49 or 61  key midi controller for the G-Force Re-Strings rack extension in Reason. I use it quite extensivly in a live project I am in and need to have better hands on control (plus some stage vibe) than what my current controller gives me.

Here is a screen shot of the rack extesion. I would like most of the variables to be mapped to faders and post... especially the lfo's (speed, depth) envelopes, phaser controlls, ensenble controls, vol.... other stuff is meh.

https://www.dropbox.com/s/j0u8av1duxy2ltm/Screenshot%202019-10-15%2018.07.00.png?dl=0

Thank you.


rtek1000

Maybe you need a more powerful controller, maybe from the STM32F4 line.

A serial port can be either hardware operated (dedicated block for this function, which can operate autonomously) or can be software operated (and data is handled via program). Most microcontrollers have only one hardware serial port, but usually many software serial ports can be added, depending on how many input and output pins the chip has.

See:

Quote
MIDI is a serial protocol that operates at 31,250 bits per second
https://www.arduino.cc/en/tutorial/midi


Quote
I tried to use the SoftwareSerial library for MIDI (by 47 effects), but it seems I get regularly corrupted/unexpected messages.
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The problem with SoftwareSerial is that while it is receiving a packet the Arduino is unable to do anything else - that includes reading bytes from the RX buffer, so it will easily overflow if you send things too rapidly. With HardwareSerial you are able to read from the buffer while it's receiving data, so overflowing is less of a problem.
https://arduino.stackexchange.com/questions/38567/softwareserial-too-slow-for-midi

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Grumpy_Mike

Not too sure what you are asking for here.

Are you asking if it is feasible or do you want someone to supply you with a schematic or write all the code for you?

For help we need an actual question.

rtek1000

Perhaps another great option would be to use an FPGA where hardware blocks for data processing could be created instead of a software-emulated serial port.
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PieterP

Perhaps another great option would be to use an FPGA where hardware blocks for data processing could be created instead of a software-emulated serial port.
What are you talking about? Using an FPGA just for UART communication is insane.
Even the most basic Arduinos can handle MIDI just fine.

Pieter

Grumpy_Mike

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What are you talking about? Using an FPGA just for UART communication is insane.
I would second that thought.

rtek1000

#6
Oct 21, 2019, 06:43 am Last Edit: Oct 21, 2019, 06:47 am by rtek1000
Yes, it's true, ops, I understood ports instead of keys. Imagine trying to use 61 MIDI ports, what processing would be needed?  :D
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brorgustav

What do you mean with 64 inputs?  If you want to build a midi controller with alot of keys you need a microcontroller with alot of GPIOs. My keyboard with 32 keys uses 16 gpios. Also you might want to get a M0 just to keep it fast while scanning keyboard-matrix and also sending MIDI

Grumpy_Mike

#8
Oct 21, 2019, 12:20 pm Last Edit: Oct 21, 2019, 12:24 pm by Grumpy_Mike
Yes, it's true, ops, I understood ports instead of keys. Imagine trying to use 61 MIDI ports, what processing would be needed?  :D
Not much different, an Arduino Due would do it if you used a bunch of XR20M1170 or similar chips.

Like the SC16IS740/750/760 or the SC16IS752, SC16IS762.

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