Hello,
I'm completely new to this whole maker and arduino business but I am willing to learn!
I'm wondering if anyone can advise or point me in the right direction.
I'm looking to add MIDI fucntionality to a guitar effects stompbox pedal (The MXR M3OO Reverb to be precise).
I love this little pedal. It has everything in sound and formfactor and functionality that I could want, except: MIDI function.
This pedal has 6 reverb styles. What would be amazing is if it could also have MIDI integrated so it could store or recieve instructions to change reverb styles as settings depending on the MIDI command. I'm sure most would find this useful, but for my part, I run a backline rig where all my pedals are hooked into a MIDI switcher and I control the switcher with a MIDI footpedal controller at my feet. If this little pedal could be modified to save presets (reverb style and nob settings) then recall them when the MIDI controller sends a new pedal order preset that would make this pedal amazing, particularly if I/you wanted to have several different reverb styles during a single song/performance.
Can I get suggestions where to start? What I need to learn or gather? Perhaps opening up the pedal and posting images to let folks on here see if the MXR M3OO Reverb's current mechanics allow for such a mod? What Arduino would be best to use for such a mod? Etc.
That seems like a "big project". (A lot of "small things".) And are you willing to risk destroying the stomp box?
The additional electronics probably won't fit in the existing box. I've caused myself a lot of trouble trying to "squeeze" a design, and a big box with lots of space makes everything easier. (That's not such a big deal to a manufacturer who can make a small custom surface-mount PC board... It's amazing how much stuff, and the amount of processing power, is in a cell phone. But as a hobbyist I like more room to work.)
You'll probably also need a schematic. (I'm not asking to see the schematic but you'll need it. )
Switches can be replaced with relays. (A relay is an electrically operated and electrically-isolated switch). Relays can also be used if you want to switch back-and-forth between MIDI and manual control.
There are solid state relays and digital switches but there can be "issues" with audio it's hard to beat a pair of mechanical contacts that work exactly like a manual switch.
Relays require a driver circuit (the Arduino can't supply the voltage & current needed for a relay coil) but you can buy relay boards with one or more relays and drivers built-in. Otherwise it's pretty easy to control relays.
And there are digital pots (potentiometers). There are few different digital-pot interfaces and the software is a little more complex than driving a relay but it's not too bad. (And there can be a few "quirks" sending AC audio signals through a digital pot.)
There are MIDI shields (add-on boards) for the Arduino or you can build one yourself. And there are MIDI libraries for reading or generating MIDI messages.
It doesn't take much processing power to send a few MIDI messages so I'd guess that any Arduino would work. You may need to count-up the required number of inputs (MIDI and any other added switches) and outputs (relays & digital pots) but I think a basic Arduino will have enough.
)