This new firmwere has a better PID control. First, the temperature read is using a logaritmic function. I've measured the temeprature and also the voltage drop over the thermocuple and the amplifier output and made a graph. With that I get the function implemented in the code. The code will enter sleep mode if the iron is not used for a certain amount of time. In the menu, we can go to settings and change the sleep time or the preset temperature, which is the temperature the iron starts. This values will get saved on the EEPROM so they stay there.
You could change all this variables in the initial code if you want. I might make a kickstarter on this board soon. You would receive the board, components and a bunch of videos to learn electronics. Thank you!