4 Pin Pwm Fan Control

I am working on a project for school and this is my first time working with Particle/Photon. The project has to have two photons communicate and together complete a task. My project is using a one wire temp sensor to display a temperature value from the inside on a computer and the second photon will read that value and control a 4 wire PC fan. I have got the Temp sensor working and everything but i cant seem to find enough info to help with the fan side of the project.

I have seen some info on pwm fan control but i cant seem to find the info i need. I just need help coming up with code to control the fan with tinker and with that i could do the rest and code it to use the temp value like i need.

I have it hooked up but it just goes 100% with no change in speed when trying to tinker D1. I have read it might be the PWM freqency has to be changed but im lost.

It requires special pulse timing to control the 4 wire fan speed.

Search the web for Arduino 4 wire fan control for more info.

This forum has threads for controlling the regular 2 wire and 3 wire fans speed which I and others have done before successfully.

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You should also attach a schematic of how you wired the whole setup - don’t make people trace your wires on a suboptimal photo :wink:
Are you sure you are controling the control wire and not the sense wire of the fan?

In any case, you may want to read the sense wire too. But make sure there are no pull-ups that bias the sense output to more than 5V on your target setup (e.g. motherboard).

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