Posts: 1
Joined: Thu Oct 18, 2018 12:09 pm

Building a midi controlled LED Bar

Thu Oct 18, 2018 12:19 pm


I'm a musician and I'm trying to make our live shows a bit more entertaining. As the lead vocals and synth, I want to show the audience what I'm playing when I'm "hidden" behind my keyboard.
I've thought of putting a LED Bar on the front (audience wise) side of the keyboard and triggering different parts of the LED Bar depending on the note I hit on my keyboard. I'd basically like to render a simple piano animation on these leds whenever I hit a key. For example, when I hit a note on the left of my keyboard, a rectangle shape will light up on the left side of the LED Bar, letting the audience see which key I just hit.

Do you think it's possible ? I'm quite new to the RPI / Midi abilities so I don't really know where to start ...

Thanks for your help, and don't hesitate to tell me if it isn't clear enough, my english isn't quite perfect :)

Thanks a lot

Posts: 234
Joined: Wed Jun 20, 2012 2:51 pm
Location: Southampton, England

Re: Building a midi controlled LED Bar

Fri Oct 19, 2018 11:16 am

It is certainly possible, assuming that your keyboard has a midi output already available. You need a midi input on the Pi, and although you can build one which links into the serial port GPIOs (midi is a serial interface afterall), the particular speed that midi runs at is awkward to match. Buying a usb midi port is probably easier, cheaper and faster.
You then need to read the input - there are a number of midi libraries available for python which make it easy - and generate an output triggering the light. For a stage show lighting one small LED directly from the GPIO is not going to be enough, so you probably are looking at using a transistor to switch a more powerful light at a minimum, or triggering a professional rig, perhaps through DMX. It depends on your ambition and budget. Then you just decide the balance between resolution (and hence cost) and ease. Do you have one light per note, or one note per octave, or maybe link it to which note in the scale is being played and have some way of telling the controller what key you are playing in so tonics, thirds and fifths get a big light but seconds and sevenths a small one.

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