nice job, but Raspberry Pi is too expensive, an usb watchdog can do the same work, Only 7$ or less.
Is this USB watchdog for 1 PC?I use my Raspberry Pi for many machines and you can easily extend the number of GPIO pins to control even more. Also the RPI can control simple boards like ESP8266, which costs only $2, not $7.
Also I'm using the RPi like a main station. Connected with a simple usb cam to watch what is happening there. Also when I make the new ventilation it will be controlled from the RPI
Now I'm making an rearagment of the farm, but after everything is done. I have a ton of sensors to connect.. for temperature, moisture, water level if something unexpected happenes. And many more of course