This project uses an arduino proxy PWM signal to support Noctua and other low-speed silent fans, machine is HPE Microserver Gen10 Plus V1, and providing second fan interface to cool down iLO chip.
Max-Sum's connector pin define.
Connector is 2x3 PHDS2.0, 红星电业 HX20017.taobao link
Schematic diagram
Arduino Nano Mini, taobao link
TurboFan 4010, taobao link
An RPM translater is implemented to generate the corresponding RPM pulse signals (2 pulse per revolution) based on the input signals from the HPE, which uses delay when the RPM is less than 900, and PWM output otherwise. Of course this function is useless on the HPE, it just needs a pull down signal to confirm the fan is present.
The HPE fan is rated at 6100 RPM, the Noctua NF-A8 PWM is 2200 RPM, Air Flow is 1/3 (55.5 vs 146.88 m³/h), and Static pressure is 1/10 (2.37 vs 22.8 mm H₂O). So I map with the duty cycle from 0.1 ~ 0.2 to 0.5 ~ 1.0. min dutty is 0.5.
