Questions tagged [midi]

Musical Instrument Digital Interface

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69 views

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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1answer
70 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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1answer
34 views

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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1answer
183 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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1answer
73 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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1answer
303 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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1answer
95 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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1answer
66 views

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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4answers
2k views

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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1answer
132 views

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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2answers
153 views

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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0answers
66 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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3answers
108 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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1answer
193 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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3answers
351 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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2answers
122 views

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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2answers
192 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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4answers
331 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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3answers
95 views

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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1answer
1k views

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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1answer
57 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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1answer
114 views

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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2answers
480 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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2answers
452 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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1answer
160 views

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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2answers
213 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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2answers
285 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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1answer
66 views

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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2answers
1k views

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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1answer
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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1answer
122 views

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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2answers
1k 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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2answers
119 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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1answer
331 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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1answer
93 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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1answer
192 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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1answer
135 views

Several MIDI over USB Device

I'm looking at creating a "specialized" MIDI over USB device for a project I'm working on and my requirements have gone beyond that of the Arduino/Pi/etc, due to limited I/O. I am very much a beginner ...
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2answers
417 views

Extra pins on MIDI connector?

I'm designing a MIDI project using these SDS-50J connectors. The datasheet provides a suggested footprint diagram and labels the pins 1 through 5: It does not, however, label the bottom-most two ...
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1answer
693 views

Is my PCB layout ok? (ATMEGA32U4, WizNet W5500, Ethernet)

I want to design a device that listens to certain network communication and calculates a MIDI clock signal out of this information. The MIDI output is via classical MIDI port or via USB MIDI. I am ...
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1answer
535 views

Best Arduino for Midi-Board

I came across this device recently: The Loupedeck. Now, most reviews say that it's built very poorly and a simple Midi controller paired with Midi2LR will get the job done better and cheaper. But, I'...
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2answers
242 views

Calculating Component Values for MIDI synth

I am reasonably new to this, and I am trying to find the calculations used to choose the component values in this circuit. Concerning the Optocoupler, from what I can work out: 6N139 Forward ...
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9answers
3k views

Reading a huge number of analog sensors in real time

I'm trying to build a MIDI-like controller that has a neck like a guitar. On that neck, there is a huge matrix of pressure sensors. The controller will emulate 3 strings. The way this works is: ...
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2answers
1k views

Why is my MCP4822 DAC not outputting 0 V?

As part of my MIDI to CV project I am using an MCP4822 (datasheet) two channel 12 bit DAC. After much toil I have everything working as planned, except for the fact that even when initialised with ...
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2answers
757 views

Is it possible to test a MIDI device through its connector with a multimeter?

I have a Fluke 115 multimeter available that I'm hoping has capabilities to register (even with low fidelity) any MIDI signals flowing out of a handful of devices. ...
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2answers
530 views

Burnt Diode in MIDI Keyboard? [closed]

A while back I think I may have plugged the wrong power adapter into my MIDI keyboard and it started to smoke and then never turned on again. So... I popped it open and it looks like it's a burnt ...
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1answer
857 views

Connecting MIDI patch cable DIN connector shielding and pins 1, 5

I am building myself a MIDI patch cable. According to resources such as http://www.leadsdirect.co.uk/technical-library/pinouts-wiring-diagrams/din-midi-wiring/ the middle pin of the DIN connector (pin ...
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4answers
367 views

MIDI source selector switch

So I am looking for a way to switch three signal lines between 1 source and another, the idea being I want to switch a MIDI Port on my device between thru and out modes, but also can't have any delay ...
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4answers
4k views

4N35 opto-isolator for MIDI input does not work?

I have the following circuit which I would like to use to connect a MIDI enabled device. I am not getting any signal on pin 5, could it be because the resistor from the base to ground in too small? I ...
0
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1answer
81 views

Minimum distance between inductor beads and an RF transceiver?

I there a minimum distance needed between the beads and the RF transceiver? Like below ... the connections do not really matter, just if there are requirements regarding the distance between the bead ...
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1answer
1k views

I cannot get opto-coupler H11L1 to work as MIDI Input

I received my H11L1 opto isolators (yeah) to use for my MIDI input(s). However, I cannot receive anything (and tried various circuits). According to the H11L1 (see datasheet) an example circuit is: ...