Making a MIDI-controlled momentary switch?

TheBigDipper

Long story made short. My Rivera amp has a 3-button footswitch (the FS-7) that switches channels and toggles the channel boosts on or off. It also has LEDs to show the status of the settings. It connects to the amp via an 8-core cable and an 8-pin MIDI plug. I've learned that all the functional bits are actually inside the amp and the 3 footswitches just send momentary signals to the amp circuits. I'd like to try and swap the footswitch out for controlling those functions via MIDI using a standard, generic MIDI controller, like an MC-6 or whatever. 

Rivera makes a product that does just this to replace the FS-7 footswitch - the FS-7M (M for MIDI, I guess). It plugs into the back of the amp instead of the FS-7, receives a MIDI command and gives the amp the momentary switch pulse it needs to change channel, etc. But it's very rare second hand, old tech, very old school and buying a new one from Rivera would cost me approx £300. Its not worth it to me. 

But I thought I might be able to have a little project to build my own. But I have no idea where to start. How would someone build a MIDI-controlled momentary switch? A kit? Can anyone point me in the right direction?

Petrogli

My approach would likely involve an Arduino as the brains as it is a relatively easy to program device and the midi libraries are well supported and documented.

You need to consider getting midi messages in to the controller, and the easiest route is to use a shield such as https://coolcomponents.co.uk/collections/arduino/products/midi-shield though there are plenty of schematics available to bring midi data in to a microcontroller that could be used if you don't mind diving into a little bit of soldering.

You also need to understand the switching requirements for the amp. You will probably want to trigger a relay that has sufficient capacity to handle the voltage/current that the amp switching circuit has. Like the midi side of things, you can get relay boards that interface with the Arduino that take the work out of assembling a circuit.

Then it would be a case of building out the code. Start small, ignore midi for the start and hook up a relay to the Arduino and write some code (or steal it from the Internet) to toggle it on and off. Check this works with your amp.

Then write some code to accept midi inputs and do something like flash the LED on the board when, for example, a midi CC message on the correct channel is received.

Then hook it all together.

Cheers,

Neil