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Joined: Wed May 15, 2019 12:25 pm

Controlling RGB Fans (Thermaltake Riing or Corsair LL Series)

Wed May 15, 2019 1:08 pm

Good morning all,

I am new to the PI, but have done some decent Arduino projects in the past. I am working to build a PI that will monitor, control and report on my water cooling system for my new PC build this summer. The system will be Theme-based and as such, I want to control the LED lights on the fans for each radiator (one red, one blue). I am looking to use the 24 port PWM controller from Adafruit to provide PWM signals for each fan individually, I would like to control the LEDs on those fans as well. I will need 10 - 12 PWM channels for fans, two for water pumps and however many I need to control the RGB on the fans and in the case (so a 2nd 24 port module as they can be daisy chained on I2C). The idea is dual loop water cooling for CPU/MB and GPU separate (two pumps, two loops). Each loop will have 4 of the RGB fans on it (I do not want to use the built-in controller). As loop temperature increases from ambient I want to start the first fan and engage its LEDs, if temp continues to rise, start fan 2 in that loop and its LEDs, etc..
I currently have a web-based dashboard with three temp sensors to begin my pre-alpha testing of this project

So to my question... Does anyone have any experience with these fans? I think each one may actually be an Ic2 device based on the way the factory controller can make them sing and dance...

My backup plan is to get just pure red and blue fans for each side of the case and then dim/brighten them based on fan speed PWM Signal (that way a quick visual of the case will tell me the basic temp of each loop (2 fans on dim=cool vs 4 bright ones=getting pretty warm)

Thoughts, comments, concerns?

Has anyone used these Adafruit devices with the Pi? any feedback there would be very helpful?
here is my 1st gen dashboard -- the idea is this will be displayed on the 7" Pi touch screen inside the main computer case (it's an all glass front)
PiTemp.PNG (68.6 KiB) Viewed 1526 times

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Re: Controlling RGB Fans (Thermaltake Riing or Corsair LL Series)

Fri May 17, 2019 7:30 am

The actual fans are not I2C, but the controller chips on the PC MB usually are. I quote Wiki. The control signal for PC cooling fans is a square wave operating at 25 kHz, with the duty cycle determining the fan speed. Typically a fan can be driven between about 30% and 100% of the rated fan speed, using a signal with up to 100% duty cycle. The exact speed behavior (linear, off until a threshold value, or a minimum speed until a threshold) at low control levels is manufacturer dependent.

Multiple PWM tasks can tax a typical RPI. For lots of fans I would look for a suitable PWM hat that will take the PWM task from Software and place it in hardware. Or use a chip like ... X31785.pdf
..the only thing worse than a stupid question is a question not asked.

Posts: 5
Joined: Wed May 15, 2019 12:25 pm

Re: Controlling RGB Fans (Thermaltake Riing or Corsair LL Series)

Fri May 17, 2019 9:16 pm

The PWM I think will be easy with the Adafruit PWM controller, I am looking for controlling the color/intensity of the RGB LEDs

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