What programming/technical projects have you been working on?

Still working on my personal link sharing website, off and on. I added a way to pin tags to the sidebar on the front page. (They are just buttons on mobile unless you switch to landscape mode.)

https://skybrian-links.exe.xyz/

I have been picking up my old lisp interpeter I started back in 2016 (I think). It already had support for proper tail call optimization and was fairly lean and easy to grasp (for me). I got stuck on two major features back then. One; hygienic macro support. Two; a tool for wrapping arbitrary golang code to make it callable from the lisp code.

So being a modern developer I pointed Claude to the repo and pointed it to the racket documentation about hygienic macros and instructed it to work in a TDD like manner. It is amazing what it can spit out, but it tends to be like most developers and omitt edge cases so I keep insisting it to check the code coverage to make sure the test coverage doesn't degrade (it sits well over 90%). Apart from the new macro support (almost finished, just need to add support for syntax-case) and the tool for wrapping golang libraries it has also helped me add a require/module system. Lots of fun, and a bit addictive.

Next step, once the macro support is finished, will probably be to rewrite the parser. It currently yacc based, but I'd like to create one using the new SIMD capabilities that is experimental at the moment.

I was part of one team at this weekend's hackathon at my city. I got asked to be a part just on monday woth hackathon starting friday!

The team, from which I knew only one person, needed someone knowledgeable in electronics and soldering. They were making knee part of exoskeleton (just the knee) aiming for it to be a help when seniors come up stairs. They already had the hardware part - the thing that goes on your leg and all the gearing inside and motor mount. The weekend was about electronics and programming and making it work.

The aim of the project was to make it affordable, plastic parts were 3D printed, metal bars were just simple bar that was shaped to correct shape, in the ways of powering it there was motor from battery powered drill with correspodning battery (can be bought for like 20-30€), electronics were just potentiometer for knee angle accompanied by two accelerometers (one on thigh, the other on lower part), heart of the electronics was ESP32.

My job was to design circuit on protoboard and make the electronics work. I used connectors for everything, aligned inputs in one way and outputs rotated 90 degrees, made/crimped all the cables, made MOSFET motor driver and fixed everything twice as we found bugs (bad solder joint, burned potentiometer, bad contact in connector, ripped wires...).

At around halway through the hackathon we were finished with all the hardware work and mounted the hardware to team member's leg and then software guys took over. They went up the stairs with our "cyborg" and gathered data. Then they run neural network on top of data to train it and recognize when the person is actually going up the stairs. Then they made this run offline on ESP32.

After midnight on sunday, with only 8 hours to spare, we made it work! The ESP32 recognized the movement of the leg and engaged the motor to help with walking up the stairs!

I was never part of such team and I was never on a hackathon. It was great weekend and I enjoyed much more than I ever imagined. What a great way to spend time with enthusiastic people. And lose many hours of sleep at the same time! :-D