Adjust Firmware so no fans spin while idling

[sensebellum 2]

I was wondering if it would be straightforward to adjust the Ultimaker 2 firmware so that the fan, particularly the extrusion head fan, does not spin while idling - a state such as after turning on the machine.

It is incredibly noisy and does not seem to need to be on during these times so I would like to disable that feature in the firmware.

Before I dig in, has anybody already done this?

 

[IRobertI 520]

The back/third fan is hardwired to power so it cannot be disabled in firmware unfortunately. On future versions of the PCB this feature will be added.

However, the fan shouldn't be noisy so I would contact Ultimaker and see if they can send a replacement to you. Changing the fan yourself is fairly straight forward.

 

[Daid 306]

The back/third fan is hardwired to power so it cannot be disabled in firmware unfortunately. On future versions of the PCB this feature will be added.

And, the firmware change for this has already been added. (Sadly, the first prototypes of this new board had a problem with the motor drivers, so it will take a bit longer before it's rolled out). But once this new board is in new machines this feature gets activated automatically.

Our electronics guy also proposed to note down a small schematic so people could wire this up themselves if they want. We still have spare pins in the board that could be used for this. (It should just be a transistor and a few resistors)

 

[donmilne 2]

However, the fan shouldn't be noisy

Everything is relative. In the near perfect silence on my computer room (I have a very quiet PC), the UM2 fan is the loudest thing running. This may be what the OP is talking about.

 

[jbeale 0]

And, the firmware change for this has already been added.[...]

Our electronics guy also proposed to note down a small schematic so people could wire this up themselves if they want. We still have spare pins in the board that could be used for this. (It should just be a transistor and a few resistors)

 

I would definitely be interested. I assume the fan turns off whenever the head heater is OFF and also the head is below XX C temperature(?) I replaced the metal side-fan bracket with a duct printed in PLA, so I don't want to turn off the head fan until things are cool enough not to start melting the duct. But I don't like the always-on fan noise at idle, and I'm sure it will eventually wear out.

I can do the switch circuit myself, just let me know which pin number the FAN-ON signal is coming from. (Also, how much current at what voltage, goes into that fan?)

 

[Daid 306]

I can do the switch circuit myself, just let me know which pin number the FAN-ON signal is coming from. (Also, how much current at what voltage, goes into that fan?)

 

The fan is a 5V fan, not sure how much amps it draws, but not that much. (too much to drive it from a pin, but not so much it takes a heavy FET. A BD679 will most likely work, as that's also used for the UM1 fan.

The pin currently controlled is PJ6, however, this is not routed to any of the external pins on the board you have. But I could easy add another pin to be set with this state:

https://github.com/Ultimaker/Ultimaker2Marlin/blob/master/Marlin/temperature.cpp#L508

(PJ6 is not mapped to any Arduino pin numbering, which is why I'm using registers directly)

 

[eldrick 65]

If one was making changes to the fan behavior, IMHO it would be very useful to keep the fans running for a minute or two after a print ends, in order to keep PLA from baking in the nozzle during cool-down.