Questions tagged [midi]

Musical Instrument Digital Interface

34
votes
4answers
33k views

Make a custom plastic case

I have worked on many electronic DIY projects like MIDIbox (http://www.ucapps.de/), it always was fun and working but at the end, the problem was that I ended with a cool gear, but in a poor casing, ...
17
votes
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: ...
11
votes
4answers
5k views

MIDI sequencer timing accuracy using the Arduino

I build these music sequencers. Only it's not exactly a sequencer, it's a physical interface for a sequencer. The sequencer is an application that runs on a laptop that the sequencer connects to, ...
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 ...
8
votes
1answer
1k views

Arduino serial communication protocol design

I make a drum sequencer interface for electronic music. It uses an arduino mega as it's microprocessor, and currently it interfaces to a Processing program that I wrote for serial communication. From ...
7
votes
2answers
11k views

Is there any reason why using a baud rate of 31250 on an Arduino MIDI project could cause problems?

I have a 600 pulse per revolution optical encoder (and some other stuff) connected to an Arduino Uno (tried it on r2 and r3) through the interrupt pins 2 and 3. While waiting for a my MIDI jack to ...
7
votes
4answers
2k views

Pressure/Force sensor

One of my students are planning to make a simple musical keyboard with PIC microcontrolers, using MIDI output. The main problem now is about the pressure/force sensor. I've found a good alternative ...
6
votes
5answers
1k views

Are these MIDI circuits equivalent?

I've been creating a MIDI Thru box project and was trying to avoid having so many resistors. Points A-G may (or may not) have a load connected to them. Are these equivalent, or do I really need to ...
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 ...
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 ...
5
votes
1answer
993 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 ...
5
votes
2answers
739 views

Electronic component that detects angular rotation like a potentiometer, but endless and digital

I am relatively new to this whole scene but am wanting to start a small project sending midi-signals from a board I am creating. That said, I am a big fan of these endless, smooth digital ...
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
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 ...
4
votes
1answer
419 views

Hardware based MIDI decoding / synthesizing

I have a lot of old MIDI equipment that was recently given to me by a retired music teacher. I have a lot of interest in it, and would like to make a MIDI synth. It does not need to be high quality or ...
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
1answer
348 views

What's wrong with this simple PCB design? (midi synth)

I am designing a simple synth with Arduino (just the Atmega IC) and it works fine. The only thing is this annoying clicks I barely hear constantly if I raise the volume somewhat. I had this problem ...
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, ...
4
votes
2answers
3k views

DIY MIDI knob Controller

What would it take for me to build something similar to the mockup below?
3
votes
1answer
963 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 ...
3
votes
2answers
163 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 ...
3
votes
1answer
127 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 ...
3
votes
2answers
376 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 ...
3
votes
2answers
2k views

MIDI To Polyphonic Square Wave on Arduino

I've been struggling with this for a few days now, and I would really like to get on with my project. Unfortunately this is holding me up. What I am trying to do is retrieve MIDI signals sent over USB ...
3
votes
2answers
292 views

Connector Choice for Arduino/MIDI Bridging Interface

I'm in the early stages of planning a MIDI-mapping component that I can plug into my Alesis DM-6 drum kit so I can ultimately play it through Rock Band 3. I know there are commercial options out there,...
2
votes
4answers
3k views

Converting old organ keyboard to MIDI

I have a very old keyboard, a CASIO MA-100 that I want to convert to a MIDI keyboard: Being a programmer and a digital electronics enthusiast, I know how to do it, but I could use some help to save ...
2
votes
1answer
993 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 ...
2
votes
3answers
161 views

Opening serial port for reading, when data is already flowing

I have a drummachine (Roland TR505, but all of this would be true with any other device) sending a byte 11111000 (Timing Clock MIDI message), 48 times per second, ...
2
votes
2answers
221 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 ...
2
votes
2answers
531 views

Difference between H11L1 and H11L1M

What is the difference between a H11L1 and H11L1M opto coupler? (I want to use it for MIDI). Datasheets H11L1 H11L1M If I check the data sheets, I see some different values, but for me it is ...
2
votes
2answers
627 views

Expressiv MIDI guitar implementation

Rorguitars claim to have the best MIDI* guitar system on the market. Their website says: Our guitars do not have MIDI pickups. There is NO pitch detection to send the MIDI signals. Our instruments ...
2
votes
4answers
284 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 ...
2
votes
2answers
379 views

MIDI-activity LED

I built a simple MIDI-output circuit (as seen here: http://www.notesandvolts.com/2015/03/midi-for-arduino-build-midi-output.html). I now would like to add an LED to that circuit that should be on ...
2
votes
1answer
325 views

MIDI out waveforms very different between two devices

I have two MIDI output devices: an Axiom49 keyboard and a Korg SQ-1 step sequencer. The Axiom49 drives a MIDI input circuit that I've built using an Arduino just fine. The Korg SQ-1, however, does not ...
2
votes
2answers
3k 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: ...
2
votes
2answers
158 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 ...
2
votes
2answers
105 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 ...
2
votes
1answer
282 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
4answers
7k views

USB-MIDI Interface with STM32F4 Discovery?

I've got an STM32F4 Discovery Board and I'd like to use/configure it as an USBMIDI device but this standard device class is not (fully) supported by the USB libraries supplied by ST. Any hint? Any ...
2
votes
2answers
865 views

MIDI - clockless serial with TI MSP430 MCU software?

I'm planning to make a small MIDI transport box ( an encoder plus 6 buttons) but i don't have a lot of experience in serial communications( I have used shift registers but that's all) I would like to ...
1
vote
3answers
66 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 ...
1
vote
2answers
338 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 ...
1
vote
4answers
91 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 ...
1
vote
1answer
961 views

ATMEGA328P send MIDI via USB

I've created a circuit on my breadboard including multiple shift registers and a teensy 2.0++. My program takes inputs from the shift regs and converts them into MIDI messages. Using my teensy in ...
1
vote
3answers
181 views

How to stretch high frequency digital signals (e.g., MIDI) into the audio range

I'm curious about the possibility of sonifying MIDI data, which has a bitrate of 31250. The range of human hearing extends to about 20kHz, which means that the fastest bits of the signal would lie ...
1
vote
1answer
43 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 ...
1
vote
2answers
403 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. ...
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,...
1
vote
2answers
1k views

5-pin DIN socket advertised as MIDI, not the same as on my MIDI gear

I bought a 180-degree 5-pin DIN chassis-mount socket dirt-cheap for a project, but I saw that it looks quite different from the MIDI outs on my MIDI gear; I did some research but couldn't find any ...
1
vote
2answers
28 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 ...