Since last week I got something like 15 little packets from AliExpress, so I finally have all the parts for my electronics builds and can get to finishing them.
MIDI Expression Controller
The guts of the thing are little more than a WaveShare RP2040, a tiny OLED display and a pushbutton, but they need a little bit of software to act as a MIDI USB device, so I’m playing around with CircuitPython.
And I must say it is pretty amazing for this kind of project–you get I2C, MIDI over USB and hot code reloading out of the box, and what took the most time so far was soldering some pins on one of the boards and wiring up the breadboard:
The only drawback is that CircuitPython seems a little slow to send MIDI updates, so I might switch to Arduino/C++ later depending on how well it performs in use.
And picking up on last week’s idea about using OpenSCAD hulls, I started designing the case for it by wrapping the linear pots in a nice curvy hull:
Not Quite Smooth Sailing
After the first round of tuning, and since we now have a new set of Teenage Engineering Pocket Operators in the house I printed out this Pocket Operator case as a test:
This was a good test for troubleshooting first layer printing and Z-axis flattening, but printing the buttons has so far proven impossible since my printer has a lot of trouble with repeated filament retractions and precision moves, and reducing speed didn’t help.
So I started going doing simpler test prints to troubleshoot one thing at a time:
Part of the tuning involved getting some pliers out and tightening the X and Y axis belts, which have become loose over time.
However, one of the bolts froze and required a lot of torque that partially damaged the Y axis mount, so I ended up having to print a new support piece:
This is when I realized my extruder is having a little trouble (that’s the reason for the little holes in some layers). So I’m again looking at getting a new printer, preferably something with an all-metal construction (fortunately, the market seems full of Ender 3 clones).
And while I sort out the printing side of things, there’s plenty of time for doing some more electronics…