Hi, I want to regulate the fan speed of my Noctua fans through PWM & GPIO. The fans are supplied by an external 12V power supply. I have tried to control the speed through a GPIO-out node and a slider sending a 0 - 100 PWM signal. What am I doing wrong? Are there any example flows available? I w…

You don't say, but I assume you are using a Raspberry Pi. Be VERY CAREFUL with the GPIO pins on the Pi as they work at 3V3 logic levels. DO NOT connect them to anything higher than +3.3V otherwise you will destroy the device. The best way to control a fan is with an H-bridge module. The inputs wo…

Here's a link to my slot-car racing project. This used a PWM pin driving a power transistor. [image] Slot car racing - - - just pure fun Share Your Projects I make no excuse at all - this is just pure fun. My students will love it !!!! I've just bought a slot car racing…

Is it the pwm that is not working? If so, then show us how you have configured the GPIO node.

Hi Colin, I have just connected at 0-100 slider sending a PWM signal to a GPIO-out node. I would like to control the fan from 0% to 100% RPM.

The is going at full speed all the time, its not responding to the slider so I do not know how to achieve the desired fan speed.

A circuit digram would be useful to see how you have connected things together. You could also try controlling an LED (rather than your set of fans) to just make sure the Pi is working.

I dont really know which GPIO pins I need to connect the 2 PWMs on that are not the power supply

As the others have stated we will need a wiring diagram. Do the fans have 3 or 4 wires going to them ? Do you have any external hardware (i.e.an external PWM controller as noted below) or are you trying to do this all with the native RPi components ? Craig

As others have said, we need a wiring diagram from you - just a rough sketch would help. I've quickly looked up Noctua fans and it would seem they have some circuitry built inside them. I found this whitepaper that describes Noctua's PWM specification. On the very last page is a suggested 'Driving…

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Fan Speed Regulation PWM GPIO

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dynamicdave 9 August 2022 17:24 3

Here's a link to my slot-car racing project.
This used a PWM pin driving a power transistor.

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Fan Speed Regulation PWM GPIO

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