Questions tagged [midi]

Musical Instrument Digital Interface

9
votes
1answer
5k views

MIDI IN : many circuits

I'm building a MIDI IN to serial port RX cicruit (for Raspberry Pi, or Arduino, or anything else...) using a 6N138 optoisolator. But I find many different circuits, I don't know why there are so ...
2
votes
1answer
281 views

Minimize current consulption for MIDI input circuit?

I'm using a MIDI input circuit like the one shown in the schematic below. R1 is not touched as driven by the input device. R2 is fed from my internal power supply. The device is very low power so I ...
2
votes
2answers
2k views

Use a PC123 optocoupler for MIDI input

Im trying to connect a MIDI input cable to an arduino. To do that, I need an optocoupler, that secures the internal circuits from damage. This is the schematic as shown by the MIDI specification: ...
4
votes
2answers
7k views

Implementing a class-compliant USB MIDI device

I'm building a device that I want to communicate with a computer using MIDI over a USB connection. There are lots of USB MIDI devices that are class-compliant and thus require no special drivers, ...
6
votes
4answers
15k views

How do I hook up an LED across the tx pin on my Atmega328?

I've built a standalone Arduino and upload sketches via this method From Arduino to a Microcontroller on a Breadboard. I would like to hook up an LED across TX like on the Arduino board, so I simply ...
2
votes
1answer
992 views

Using a MIDI connector both as MIDI In and Out (not simultaneously)

In my current (Arduino) project I have (currently) 3 MIDI INs and 2 MIDI OUTs. However, it would be nice, if I can configure each of the MIDI connectors as IN or OUT by software (Arduino). The ...
5
votes
2answers
134 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 ...
4
votes
2answers
61 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 ...
4
votes
2answers
5k views

MIDI to Arduino with a 4N38 Optocoupler

I ordered a set of optocouplers the other day and was excited when they finally came in. Unfortunately, I've having a bit of trouble getting them to work. Simple on/off tasks work fine but when I ...
6
votes
4answers
2k 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 ...
3
votes
2answers
374 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 ...
1
vote
1answer
745 views

MIDI out / thru circuit questions

I made a MIDI in/out circuit, which works, however, I see I have some changes compared to some other circuits I see. In the official documentation Midi Org I see two resistors on the MIDI out circuit,...
0
votes
2answers
93 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 (...