Hello Everybody. I am hoping to build 24 button midi trigger unit. Triggering will be via 24 individual arcade buttons that each have a leaf-switch fitted. I don’t have to send continuous control (CC) messages, or even velocity information, just ‘note on’ and ‘note off’ on a particular midi channel. I would like the unit to send midi out signals via a tradition 5-pin midi in rather than midi via USB (note that there is no requirement for the unit I am building to be able receive midi signals). It is a bit of a prototype, so it would be good to avoid having to solder the connections between the buttons and the Arduino. I am presuming that my device won’t be able to draw its power from the midi device it will be sending midi information to (thus requiring my device will have to be powered by USB or perhaps its own DC power supply) but let me know if I am wrong about that, as it would be good not to worry about any type of USB (or other) connection to connect power. Also, do I need to be worried that I could inadvertently damage equipment a link up my unit to via sending some sort of damaging electrical charge - or is that an unlikely or impossible event? As you can sense, electronics are not currently my strong suite, but I think I could conceivably build this thing if I can just get some good initial advice on what arduino is best for this job. Thanks in advance.
Hi Tim
Welcome
A bit confused here
Just how would you anticipate getting power to your device then ??
Cheers Bob
Hi Bob, thanks for your reply and sorry for not being clear. To clarify, 5-pin midi can (at least in some circumstances) send power (or perhaps) even draw its required power from another midi device - along with being able to send/receive midi data. My hunch is that this is not going to possible in this instance and the the Arduino will have its own power supply, but I just wanted to double check.
Hi Tim
All clear now.
Yes the Arduino can be powered several ways or all the ones I have had dealings with could. I think that philosophy has been continued.
USB from a computer or other.
VIN. 7.5 to 12V and let the on board regulator do its thing. 12V Max to avoid overheating the regulator.
Regulated 5V at the 5V pin. This Pin can be used as an input as well as 5V output when powered by either the above 2 methods.
Cheers Bob
Hey there, @Tim329704, and welcome to the forum. Glad to have you here.
For 24 switches, I’d use an Arduino Mega 2560 R3 and a terminal block shield should make the 24 button connections solder-free and mechanically reliable. That way, you have plenty of input / output and serial ports.
If you’re not comfortable with soldering, I would probably start off with setting up a USB MIDI device while you work out the rest of the board before you move onto and using that to power your unit. When you have that all sorted out, you can grab a SparkFun MIDI Shield although it requires some soldering.
I’d still also powering it via USB instead of MIDI, at least at tfirst. While some people have managed to steal power via MIDI to to get the Arduino going (MIDI experiments: Stealing power for an Arduino - Practical Usage), it can be risky and could easily fry your board. I would probably want to test it out with a cheap, expendable arduino first before using it on the Mega.
Thanks Jane. That’s all very useful. Much appreciated.
Thanks Bob. Much appreciated. On reflection, I think I will just go with powering the Arduino from USB as it seems the simplest and safest option. Thanks again.
Hi Tim,
A go-to MCU for me personally is the Teensy - a super fast clock and great drivers for audio projects, even this MIDI one!
The 4.1 ought to have enough pins for all of your buttons directly wired to each.
Alongside this, the Pico is a great choice - a bit cheaper and lots of support in different languages.
Liam
