In my last project, I upgraded the lights in the study to display an “aurora” on a curtain of Neopixel (WS2812B) lights. I ended up with a leftover 10 meter string of neopixels, I combined those with a spare Pimoroni Plasma 2350 I had to make another project in my office, which I call the MIDI Plasma Reactor.
The Idea
Thus far, I’ve made a lot of MIDI projects for the Raspberry Pi Pico (and Pico 2). I use TinyUSB for the basics, and have adapted this person’s excellent work for more complex setups.
I’ve also made quite a few light projects using Neopixels. I decided to combine these ideas and make a curtain of neopixels that react to MIDI messages.
My son uses Synthesia to learn to play songs he enjoys, the idea is that this would add complimentary background lighting. If he’s playing notes on the left side of the keyboard, lights on the left side of the background should respond.
The Implementation
I spent a few hours knocking up the code I needed, other than the occasional math/casting goof, there was only one real facepalm. My last project used an actual grid, in which the last light in the first row is followed by the first light in the next row. As I was using a string of lights snaked back and forth, I had to add logic to flip every other row.
It took at least as long to decide on the arrangement of lights and mount them, in part because I wasn’t willing to completely take apart my workspace to do it. I spent a few hours reaching behind my setup to stick lights to the wall using Blu Tack, and then a bit more adjusting it to fill the space better (the top row needs to sit above my monitor for it to be visible while playing).
Anyway, after all that, I (halfway) cleaned up my desk and recorded a demo video, which you can check out here:
I’m pleased enough with it for now. I did notice some lag when hooking the system up to a sequencer. This is probably down to the fact that the Adafruit Neopixel library I’m using is not overly efficient. If I end up making a successor to this project, or something that needs to operate at video framerates, I’ll probably need to switch to using DMA.
Thankfully I won’t have to start from scratch. My friend shared this approach to using Neopixels with a Pico and DMA, I also found a few other projects like this one on GitHub.
Conclusion
For now, the work to date seems fine for the number of notes and the speed at which my son is likely to play, and the idle animation makes a nice fill light for my workspace. If you’d like to make something like it, as usual the source code is available in a repository on GitHub.
Stay tuned for whatever’s next.