Questions tagged [midi]

Musical Instrument Digital Interface

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Problem working with MIDI on hardware serial port on Raspberry Pi Pico 2040

I'm trying to make to make a simple MIDI communication with a Raspberry Pi Pico (2040) microcontroller (Arduino core/PlatformIO). I've successfully made it work using USB MIDI with this code (using ...
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Digital buffer/driver (74LVC1G07) not outputting signal. MIDI output circuit

I am expericing difficulties with a simple MIDI output circuit. I have checked the input of the buffer and signal is there. However, there is not signal at ouput. . At first I thought that I blew up ...
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1 vote
1 answer
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HAL USB device library transfer complete callback (USB MIDI adaption)

I have been able to implement Zac Rogers USB MIDI adaptation of the Cube MX USB device middleware: https://github.com/zacrogers/blue_usb_midi I can send USB midi messages on both F103 and F411. It ...
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3 answers
61 views

Can I substitute SN74LVC1G04 (single inverter) for SN74LS00 (quad inverter)? (re: simple GAMEPORT to MIDI cable?)

I'm trying to design a simple GAMEPORT to MIDI adapter/cable. However, the original design specifies the 74LS00 which I think is used as a buffer: http://midi.teragonaudio.com/hardware/pc_intfc.htm I'...
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Does this circuit look correct to connect DA-15 (Gameport/MIDI) to RPi (MT32Pi)?

I'm trying to connect an older PC with a DA-15 (Gameport/MIDI) to a Raspberry Pi using MT32Pi. The Gameport/MIDI is +5v and the RPi is +3.3v so I'm using an optocoupler and voltage divider. Does this ...
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Can I use two micro-USB receptacles on a single device so the user has the option of using either?

I make a USB MIDI device and am designing a new version. I'd like to have two micro-USB receptacles in different locations so that the user can choose either, for ergonomic reasons. The easiest thing ...
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Help identifying unknown IC in MIDI controller board

I'm trying to fix an Akai MPK mini MK II. The USB connector was busted, and I also found a 6-pin IC that had been yanked out by the connector. The only markings it has is "62 7" though the ...
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3 answers
100 views

Is it possible to use a Smartphone audio jack as MIDI output?

Is it possible to use a Smartphone audio jack as MIDI output? My plan is to use a standard TRS to MIDI cable, like the one Arturias Beatstep uses, to connect a Smartphone/Tablet to a MIDI device. I ...
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MIDI Output circuit not being recognised by MIDI devices

I'm trying to make a MIDI Out circuit from the Sparkfun web page (https://learn.sparkfun.com/tutorials/midi-tutorial/all). My MicroController is a 3v3 device but I'm using two Not Gates as used in the ...
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How to change from audio-out to MIDI out from same headphone jack?

I am trying to add MIDI OUT capabilities to an audio device - using the same jack. User will select in software if audio or midi is to be outputted. Currently, the audio jack wiring is as shown (R1 ...
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240 views

Add MIDI to music keyboard without disrupting its functionalities

As a DIY project I would like to add MIDI capabilities to my Yamaha PSR F51 keyboard. I've found some projects on the Internet as this one, but unfortunatelly in this way the keyboard would not work ...
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4 answers
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STM32 as a MIDI device (I'm lost)

I have an STM32F723. I'm trying to configure it so that my computer recognizes it as a MIDI device via USB. I searched the internet for examples, and read up on USB and MIDI. However, I'm lost in all ...
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midi keyboard lost 7 keys

I have acquired a korg 49 key midi keyboard which has 7 keys that do not work.as set of 5 together then 2 more 2 keys away. what could cause this issue? I have cleaned and tested the contacts and they ...
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81 views

USB and Serial MIDI

I have a project I'm working on for sending MIDI over USB or over a standard MIDI port using an Arduino Leonardo/Nano (ATmega32u4) and I can't seem to get anything to come over either port. I've ...
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How exactly does a computer know what device is connected on the USB port? [closed]

I am working on a mini that uses USB. This is probably something that I can get in the huge USB docs but if I can get a brief response I'll be happy. So since almost all devices interface with the ...
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395 views

Can I convert my old Digital MIDI Keybaord Casio CTK 3000 into a MIDI device, which gives only midi output

Recently my midi keyboard was damaged and it is not powering on, But now I realize I don't really need many features including speakers of the keyboard. So I thought I can convert into a small ...
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Sharp PC401 Optoisolator Failure

I have a trusty 2005 Edirol UA-20 midi interface, on which MIDI in has recently stopped working. After a bit of testing it appears the Sharp PC401 optoisolator / optocoupler appears to have failed. It ...
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1 vote
1 answer
351 views

Not debouncing on a MIDI keyboard

I am modifying an old 90s keyboard (CTK-450 by CASIO) to make it a MIDI controller. I'm going for an Arduino that goes over the matrix layout of the keyboard. The issue I have is with debouncing. ...
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1 answer
116 views

Sampling MIDI Via Parallel Port

I'm using an onboard parallel port on an otherwise disused laptop to try and sample the MIDI output of a very old keyboard. MIDI is a serial link at fixed 32 kbit/s, and so far i've managed to connect ...
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1 vote
1 answer
991 views

USB MIDI Host on a microcontroller

I need to interface a USB MIDI keyboard to a microcontroller host. The microcontroller will be receiving MIDI commands from the USB and occasionally sending MIDI commands. I'm wondering if there are ...
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1 vote
1 answer
103 views

Why does my MCU work better when powered to Vcc and PA1=D2 instead of Vcc and GND?

I'm making a MIDI processor, with its power coming ... directly from the MIDI signal itself, as done by the author of this page (see "Powered by MIDI" paragraph): it works well with a 100µF cap. I ...
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How can I turn a midi keyboard to a stand-alone piano using Arduino or any other way? [closed]

I have a midi keyboard, but I find it frustrating to start PC, DAW system every time I want to play. Is there a way to use Arduino to create an on the go stand alone piano. (It should work like a ...
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Is this DIN connector suited for MIDI devices?

I'm having difficulties to find PCB mount "MIDI" connectors by a supplier like Farnell, no search with the keyword "MIDI" succeeds. I know a MIDI connector is a DIN5 connector, but there seems to be ...
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What component does this symbol represent?

Can anybody please tell me the name of the component represented by this symbol (encircled in picture.)
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2 answers
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Purpose of the Schmitt trigger in this midi circuit

I came across an instructable about using midi with a raspberry pi and I was a bit confused about the first circuit from step 2. What are those Schmitt triggers for and are they really necessary? (...
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79 views

Make MIDI messages and audio signal transit in the same jack cable

I know it's a crazy (bad) idea, but still: I hate having many cables attached to a music instrument when I move in the room. Let's take the example of a Akai MPC500 sampler: it is battery powered (so ...
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1 vote
3 answers
200 views

How to keep PWM from "contaminating" analog read values on my pcb

So I'm designing a PCB for a MIDI controller with a lot of slide potentiometers and push buttons. I'm also backlighting the pushbuttons with LEDs running on PWM and I'm worried that the PWM for the ...
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1 answer
225 views

How would you design a clock in order to play triplets?

If you take a master clock (e.g. 1 Hz) it is easy to get the quarter notes (every pulse), the half notes (every two pulses), and the whole notes (every four pulses) to build a simple drum machine. ...
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2 votes
3 answers
1k views

Why optocouplers for MIDI Out/Thru?

I found this article: midi-in-through-out Credits by Zynthian I like that it has notification LEDS for MIDI in/out/thru. However, I also notice there are optocouplers for MIDI Out and Thru, while ...
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Compensating clock drift "by hand" - what have I solved?

Edit: I'm not actually looking for a solution, because short of syncing the hardware clocks (which I can't do) there isn't one. What I'm looking for is an explanation of where the magic -8.4ms I seem ...
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2 votes
2 answers
348 views

Connect MIDI input shield connection to ground with capacitor. What voltage / kind?

The midi specification mentions optional capacitors between connector shield and ground for a midi input: Neither the type of capacitor nor the voltage rating is specified. I would think that the ...
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1 vote
4 answers
579 views

Is it possible to use a DPDT switch to swap 2 inputs and 2 outputs?

I want to create a passive device with two MIDI inputs and two MIDI outputs, with a switch that has two states. In the first state, input 1 is connected to output 1, and input 2 is connected to output ...
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1 vote
3 answers
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Implementing digital control on analog potentiometer [closed]

I have an analog sound processor unit, which uses either ICs or spare components. There are four controls, which are simple potentiometers. I would like to control their levels digitally, storing the ...
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3 votes
1 answer
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Do I really need diodes to receive MIDI?

All the schematics above use a diode before the receiving pin on the optocouplers. The problem was, I never able to find the exact same diode as the schematics. Before, I'm using H11L1, but it never ...
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0 votes
1 answer
146 views

Generating a midi signal from switches or digital logic [closed]

I have a control board I have wired up consisting of various buttons and momentary switches. (For an art project) There are enough for exactly two octaves (C3 to C5). I want to connect these control ...
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1 answer
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Reverse Engineer DIN 5-pin connector

Summary I have a digitial guitar amplifier that can be controlled via a footswitch. The footswitch is connected to the amplifier via a DIN 5-pin cable. I want to be able to control the amplifier with ...
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0 votes
3 answers
1k views

Making a simple 1 MIDI IN + 1 arduino MIDI OUT merger (MIDI THRU + TX)

From the Midi DIN spec schematics we can see MIDI THRU is just MIDI OUT directly at the end of a MIDI IN. Is it possible to just add a midi signal from the arduino TX ("FROM UART") to the midi thru (...
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3 votes
2 answers
843 views

Building a midi project with Arduino + scrap components (optocoupler and diode)

Original title: 300V output Optocoupler in a 5V circuit I'm (new to this) trying to build a midi controller (in and out) with arduino and scrap. I guess I had several questions in one so I changed ...
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3 votes
1 answer
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Shaping ground plane on a 4 layer USB Midi controller PCB

I have asked about this before but I have to admit that I didn't read enough before asking and therefore was'nt able to ask the question properly. I hope I am now. I'm designing a 4 layer board with ...
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5 votes
2 answers
470 views

±12V protection for MIDI input

TLDR; how to make a MIDI input withstand shorting to \$\pm12V\$? This is a counterpart to this question, I'm asking this as I was inspired by the great answer I got there. I'm designing a MIDI input ...
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8 votes
3 answers
575 views

±12V protection for MIDI output

TLDR; how to make a MIDI output withstand shorting it to \$\pm12\$V? I'm designing a MIDI output in a eurorack modular synth module on a TRS jack (this is a semi-standard non-standard way to save ...
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1 vote
1 answer
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Verilog: MIDI receiver port fails when more than two keys are pressed at the same time [closed]

I'm designing a MIDI receiver port (using Altera CLPD MAX 7000S). The device samples the second byte it receives and outputs the binary value on an LEDs. The device works fine whenever I input MIDI ...
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2 answers
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Ferrite bead in cable or in device?

I am wondering, I made a MIDI circuit and was advised to use ferrite beads in my device for MIDI input/output. It is a similar to the following circuit (only the L1/L2 ferrite beads are important for ...
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5 votes
1 answer
1k views

How important is to have some form of electrical isolation in MIDI connectors?

I want to connect two MIDI keyboards by connecting the MIDI OUT of the first keyboard to the MIDI IN of the second keyboard, but I don't have the connector and I'm nowhere near a music store to buy ...
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What actually is MIDI and how does it function in a system?

Sorry for the primitive question but this is a topic where I'm completely blank and has been a mystery for me until now. I had some readings on the net but couldn't get a clear picture. All say MIDI ...
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3 votes
2 answers
2k views

how do I use H11L1 correctly to receive MIDI?

I was following this schematics. This is the first result on google images My Arduino Serial Monitor received nothing. I tried to replace the H11L1 with LED, and it does blink. but as soon as I ...
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3 votes
2 answers
148 views

Using audio instrument cable for 1MHz transmission

I'd like to transmit digital data together with an audio signal along an instrument cable. In more detail, I'd like to send MIDI data and the audio signal of a guitar on a single cable. The rationale ...
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2 votes
2 answers
637 views

Midi Timestamp Implementation

I am building a HID USB device (via Microchip PIC MCU) with a MIDI interface, which is functioning as intended (sending midi to the host). My intent is to make it usable by a DAW (such as Reaper), and ...
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0 votes
1 answer
97 views

Component that plays single .mid music file? [closed]

Is there a component, (that is not Raspberry Pi or other mini computer it would be an overkill), that I can use to play a MIDI music file on loop? Even by uploading it on it or program it to the tune. ...
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1 vote
1 answer
301 views

Effects of 200R (199R) instead of 220R in this circuit

I'm building a MIDI in circuit, and I found out my batch of 220R resistors are actually 199R... Can this cause problems/have negative effects for using in a MIDI In/Thru circuit ?
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