I think flash memory degrades over time. This can render any phone useless given enough years of service, but this might vary a lot between brands and usage habits. A dash cam app can kill some phones surprisingly fast.

You can easily make one by adding a thermostat inline with the power cord to a chest freezer.

Thanks for your feedback.

The rubber boots on the end of the original pumps tended to crack eventually and the hum could get annoying. The rotary one is near silent but might be a little under powered for the height of the column.

Funny that you don’t seem to see things like this around any more. Maybe smart phones etc have taken their place, but there’s something organic about this type of thing.

I miss the GPU mining days from long ago. Used to have a five old computers with potato GPUs on a time switch to do just this or folding at home as a fun experiment many years ago. It kinda worked in the earliest days but asics killed the income offset after a few months.

The old Core 2 Quad Dell with three dvb-t tuners and a few hard drives still dumps a fair bit of heat into the room.