I’ve never been a big fan of wiring 12V fans in series to try and run them at 24V. There are two failure modes added, both of which have happened to me and neither of which is good.
If one fan fails open, then the other fan stops running as well because it is in series with the other one.
If one fan fails shorted, then the other fan burns up because it now gets 24V instead of 12V.
The problem is, even if you find gpios for one or two fans (the tinybee has dedicated pins for two fans), fluidnc does not have a functionality for controlling fans
You can’t associate a fan power with stepper activity, there’s not even a static cooldown fan functionality
You will need to use the “mist” an “coolant” commmands to control the fans, and use a startup macro to run them on start…
Even with this, most post processors will shut down the coolant and mist at the end of a job, wich becomes a problem too for the static case fan…
Wiring them to the power input, matching input voltage IS the simplest way I think
Lately I’ve had a lot on me, and I’ve been putting in long hours without much sleep, and it really impacts comprehension and IQ in general. Thanks for tolerating the “sleepy version” of me.
I have edited the FAQ on the Printables listing to mention that connecting the fan straight to the power supply that feeds the board is a simple and good way to do it. The FAQ answer currently reads this way:
A: One of the easiest and best ways is to not connect the fan to the board, but directly to the power supply that feeds the board, since the volts must match anyway. Nevertheless, I connected mine to the board. The Noctua fan that I used runs on 12 Volts. However, the method I used can work with fans made for either 24V or 12V. — The key is that your fan’s voltage must match the main power supply voltage. (Most people will be using 24V power, so that would mean the fan needs to match the power supply, at 24V.) — I connected my fan straight to a spare “MOSFET” port on the Jackpot board (which, again, will match the power supply, presumably either 12V or 24V), so that every time the LowRider gets switched on, the fan comes on. It doesn’t do temperature monitoring for going on and off. It stays on whenever the LR3 is on. It was simpler for me to do it that way. Please see the port options highlighted on this schematic:
I was just studying your Jackpot case with acrylic lid, thinking of how I might modify that or do similar to improve the really cheesy mount I used to put the Jackpot on my JL1.
Your contributions are very much appreciated.