Hello im just start to explore the Raspberry Pi 3 world with its functions and possibilities.
I use the Raspberry Pi 3 for different purposes with different systems (Raspberrian Stretch, KODI & Retropie). I installed for the retropie Overclocking heat sinks andNoctua 5v Fan PWM https://noctua.at/en/nf-a4x10-5v-pwm?___from_store=de, that is connected to the 5v lane on the GPIO Pins 4 and 6. I realised, that the fan is really loud and its air flow is not needed for example when the raspberries stretch is running its background services (homebridge, time machine etc.).
The Fan has four pins (Ground, 5V, RPM and PWM). I read so many Forum discussions and guides how to connect 2 or 3 pin fans and control them with an external circuit. But until now i didn't found out how i really can measure the RPM of the Fan and how i Controller its speed with PWM with the GPIO connectors. The informations, that i found are contradictory and confusing. Do a need a resistor for the green PWM Cable, which Pin should i use etc. Also not clear is how to measure the RPM of the fan? Which fan should i connect the yellow cable to)?
Does anyone have experiences with that kind of cooling project? I don't want to destroy the wonderful Raspberry Pi.
Would be great if someone can help me out with informations about how to connect the fan and how to create the right code to control it with different speeds depending on the temperature of the CPU. Thanks a lot!