You mention that you have fans. But you have not given us any details about which kind of fans. Battery powered fans? Home fans that run off of main power? Industrial 3 phase fans? (I think I am allowed 17 more questions in this game)Do you have an arduino?Do you have information and/or hardware for controlling your fans?Have you written any code to try all of this?
Are you sure your fans can be PWM controlled? Most regular 3 pin PC fans can't. A link to a specification would be useful.If it's just the 12 hours that's causing you a problem start by running them for 12 and 18 seconds instead (which will be much better for initial testing). Once that's working you can sort out the timing later.Steve
but I dont know how to insert the pwm part
Thats mine fan https://www.silentiumpc.com/mistral-92/
I saw that fan can be controlled like that here: https://electronics.stackexchange.com/questions/62324/arduino-controlled-pwm-pc-fan