Electronics

FR2 is the brownish material that many cheap circuit boards are made of. It's a mixture of phenolic resin and paper. Apparently it's quite useful to make gears out of:

Two different sizes shown. Each has two inductors (grey bits) stuck to a capacitor (middle) with some metal end caps acting as terminals. There is a third terminal underneath the capacitor. Grid in background is 1mm, pics stolen from LCSC.

This is UV sensitive solder mask resin, applied as thin as possible using a silk screen mesh. Afterwards it's heated at about 90C for 10 minutes. This makes it more sensitive to UV light by evaporating most of the solvent.

The thickness of the board beneath it gives deceptive scale. It's about 50mm tall and the toroid is 85mm in diameter.

A open source home automation mobile robot arm!

This was my first try developing my own pcb with the toner transfer method. I did this project many years back but it works perfectly to this day.

We maintain a small fleet of RTK GPS systems (Emlid Reach RS+ units or similar). But sometimes they sit too long on the shelf and parasitic drain kicks in. The manufacturer recommends recharging every three months, but ooops, this one went too long. If the batteries are too low, the battery management system (BMS) won't charge the batteries at all when you attach the USB charger cable. In this case, the batteries were testing at 0.9V rather than the desired 3.4V.

Instrument is a Geonics EM16 VLF receiver, using in the mineral exploration industry to find buried linear conductors.

Built out my ploopy mouse today, it's been sitting on my shelf for a while. I got the self-assembly kit, had to solder on one through hole component.

I got my hands on some really weird EL panels and did a little dive into how they work. I still have no idea where to get more but I think they may be DIY-able.

A banger video about applying sintered traces to 3d printed models... BUT more interesting then that is the use of ChatGPT to "exfiltrate" unpublished formulas for the cooper plating solution.

This decade old electric cooler box gave up the ghost around 2 years ago, with the indoor outlet plug no longer working. The independent 12v input was still operational, so I kept it with the intention of *eventually* fixing it...