This is a ridiculous project, but that doesn’t make it any less cool.
“Alexzpro” has created a steam boiler (with water heated by two propane blow torches!) which drives a two-cylinder steam engine. The engine turns a motor which generates power. A regulator and some capacitors converts the power into a steady 5V supply and this is then fed into a Raspberry Pi Zero. You can read a bit more here on the Forum on which he was able to get a bit of help sorting out voltage issues. You can see a video of it in action below: