Comment by jcims
17 hours ago
Bought and rigged up a 'hand sanitizer plant' about five months into COVID. Populated the thing with thermocouples, load cells and automation with nodered on raspberry pi and a bunch of esp32s flashed with tasmota doing sensing and control. Everything talked over mqtt. Great little architecture and having it highly automated allowed me to focus on the parts that were less easily controlled for.
Dashboard: https://imgur.com/a/so7iZJX
Sanitizer run: https://imgur.com/a/iWDlNfb
Quite a lot of fun actually.
I dont need to see stuff like this. I have too many hobbies already
I had a load cell under the collection jar that would adjust heat input (via PWM to SCR) to achieve a steady output rate (dW/dt) via outer PID loop, then lower the heat to just below boiling when it got to 700mL to keep it hot but pause output. It'd play a tone, I'd swap in a new jar then resume ignoring the whole thing. (I'm lying, I'd sit glued to that thin little stream of sanitization precursor teeter on breaking up the entire time.)
I stopped messing with it right before starting to measure/vary water supply through the condenser coils so I could more directly manage reflux ratio. Also had planned a float/load cell to calculate specific gravity.
All sorts of little side quests and fun mix of art/science to get into.
You know, if any of those other hobbies start to lose their lustre. :)
(for real though, the nodered on pi controlling a squadron of esp32 workers over wifi/mqtt was really nice, in case you would have any use for such a thing in any domain)