This is a clone of the cheap T12 soldering stations, attempting to eliminate the shortfalls of cheap. Useless without the fine firmware from https://github.com/deividAlfa/stm32_soldering_iron_controller
It has provisions for a backup battery. Jumper selectable between internal and external NTC as some of the new handles don't contain a NTC, so this gives you the option if you don't want to add one to your handle. There are also jumper option for configuring different soldering handles. It is setup to use the 1.3” 6 pin OLED display.
The pinouts match the KSGER stations for compatibility with the above mentioned handles. There is no provision for the real time clock in the firmware, I see it as useless.
Some of the cheap boards had issue with the linear voltage regulator dropping out from thermal protection as the power was quite high dropping from 24V to 3.3V. This design uses a switching regulator to step down from 24V ot 5V, and then a 3.3V linear regulator for a clean 3.3V supply.
Much more information on the many models out there at the above mentioned site for the firmware. I created this as it is impossible to tell exactly what you are buying from the suppliers.
A limited run is available on Tindie.
https://www.tindie.com/products/clytle374/open-t12-soldering-station/
https://www.tindie.com/products/clytle374/open-t12-soldering-station-board-rohs-kit/