Hello everybody.
I'm quite new to this so please forgive my lack of knowledge.
Here is the fan. It is a NF-A14 PWM 140mm.
http://noctua.at/en/nf-a14-pwm/specification
I would like to have temperature based fan speed control using the WiPy 2.0.
The ESP32 datasheet has provisions for DC Motor PWM control and I have an led going up and down in brightness using PWM for testing purposes.
Would it be just a simple case of hooking up the fan and writing in the code or do you think I would need an IC fan speed controller also.
This is for a BSc computer science project.
Your help would be greatly appreciated.
Kind regards.
Marc.
4 Pin PWM Fan Speed Controller help required
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- Posts: 2
- Joined: Mon Feb 06, 2017 5:03 pm
Re: 4 Pin PWM Fan Speed Controller help required
My understanding is that most of these fans like a 25 kHz PWM signal. You should be able to generate that directly from the WiPy.
This document has more details about the 4-wire fans used in most computers:
http://www.formfactors.org/developer/sp ... m_spec.pdf
Newer fans should accept a 3.3v PWM signal, otherwise you may need to drive it through some type of voltage translation (typically just a MOSFET).
The extra wire is a tachmoeter signal that can be used to detect if the fan is actually spinning or not. The tachometer signal is open drain so it should work with a 3,3v pullup, but again, you may need voltage translation here as well.
This document has more details about the 4-wire fans used in most computers:
http://www.formfactors.org/developer/sp ... m_spec.pdf
Newer fans should accept a 3.3v PWM signal, otherwise you may need to drive it through some type of voltage translation (typically just a MOSFET).
The extra wire is a tachmoeter signal that can be used to detect if the fan is actually spinning or not. The tachometer signal is open drain so it should work with a 3,3v pullup, but again, you may need voltage translation here as well.
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- Posts: 2
- Joined: Mon Feb 06, 2017 5:03 pm
Re: 4 Pin PWM Fan Speed Controller help required
Thanks for you response.
The only reason I'm using the fan is because I have one available.
Could you recommend an easier solution where minimal external circuitry is required.
I'd like to design with high reliability in mind.
The only reason I'm using the fan is because I have one available.
Could you recommend an easier solution where minimal external circuitry is required.
I'd like to design with high reliability in mind.
Re: 4 Pin PWM Fan Speed Controller help required
If its a newer fan, then probably no external circuitry is required. I think you need a pullup resistor to use the tach (pullup to 3.3v). If the fan is moving and you can see pulses on the tach line with a 3.3v pullup then you're good.
I'd just try feeding a 25 kHz 3.3v signal on the PWM line and see if it wrks or not.
I'd just try feeding a 25 kHz 3.3v signal on the PWM line and see if it wrks or not.