It's a bit sad how deserted this community is, would love to connect more with other makers.
Let's rattle the cage a bit, who of you is here, and what are you working on?
I'll start: A wireless cryptographic keystore & signer. Keys are generated with the hardware RNG and stored AES-encrypted with the user's password, and you can request signatures via BLE.
I have built incubators for several different projects (seedlings, mushrooms, tempeh, fermentation, etc...). Learning how to control a heat distribution in a safe and efficient manner has been a bit of a journey for me. Just recently I begun experimenting with positive temperature coefficient (PTC) heaters and I am very happy with them as I feel much safer running these than ceramic/IR heat lamps and regular heating elements.
At the moment I am heating an incubator for petri dishes using a 12V/100W PTC heater with a fan hooked up to an stc-3008 thermostat. The PTC undergoes on/off cycles that keep the temperature near 26 C, but, even when setting the upper and lower control limits quite tight, the temperature still oscillates up to +/- 2 C during these cycles.
I have been studying how to implement a proportional–integral–derivative (PID) controller to avoid the on/off cycles. My next experiment is to try to control the power of the PTC with a Mean Well HLG-120H-12AB LED-driver in constant-voltage mode and the ESP32 as the PID controller.
that's so interesting, are you doing this at work or are you an avid gardener?
It's for hobby!
But I did work with cell cultures (with lab-grade incubators) in the past, and I am currently working with a company developing sensors for industrial systems. So, the concept of PID I learned at work recently. And at work I also write some firmware for interfacing sensors with micro-controllers.