I was hoping I could find some help as I am not that familiar with Marlin. I currently have an Ender 5 and I am in the process of replacing the stock board.

So here’s what I am trying to do: I have two small 12 V fans that I want to be powered on when the enclosure is above a temperature that I set using the Ender 5 interface. Basically, both fans get powered on until the temp is below (maybe a few degrees) the target temp. The temperature would be monitored by a thermistor.

I prefer this over using a separate Arduino as I find the Arduino adds bulk and lots of unnecessary wires etc.

I really would appreciate any help on this, or anyone telling me that this idea is impossible with the selected board. If it is possible, a detailed list, or edited code -- whichever is easier would be really appreciated.

  • $\begingroup$ That is strange, if I understand correctly, the fans need to go on when the temperature in the enclosure drops under a value, if you have a heated bed, that is never going to happen! Unless the print is finished and everything cools down. Marlin has default support for the opposite, the fans will go on when the temperature crosses/increases a setpoint temperature to cool the enclosure. Please explain what the purpose is of your question. $\endgroup$
    – 0scar
    Nov 23 '20 at 22:53
  • $\begingroup$ Sorry for the misunderstanding, I do mean for the fans to go on when the temperature increases beyond a point. For example, if I am printing in PLA I would want to keep the temperature relatively low, however, with ABS I doubt the fans need to be on at all. $\endgroup$
    – Tassilo16
    Nov 24 '20 at 20:25
  • $\begingroup$ As well, you said that there was default support for this. My main worry is that the pinouts that I have on the board may not work, as they are not meant for fan outputs. I know that may seem weird, but I do not fully understand the amount of voltage or current that is drawn through the pinout. $\endgroup$
    – Tassilo16
    Nov 24 '20 at 20:30
  • $\begingroup$ A pin connected to the processing unit cannot provide the current that schedules a fan or a heater, the idea is that you let a MOSFET switch the power circuit. $\endgroup$
    – 0scar
    Nov 24 '20 at 21:58
  • $\begingroup$ Oh ok, that's interesting, I will definitely look into it. Also, could I use any pinout for the thermistor, as long as I specify it in Marlin? and then a separate pinout that will connect to the MOSFET switch? $\endgroup$
    – Tassilo16
    Nov 25 '20 at 17:09

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