Can I remap a fan port on my MCU?

General Discussion
1

Basic Information:

Printer Model: Custom Ender 3 pro
MCU / Printerboard: / BTT SKR Mini E3 V3
Host / SBC Raspberry pi 4b
klippy.log
klippy (1).log (14.9 KB)

Fill out above information and in all cases attach your klippy.log file (use zip to compress it, if too big). Pasting your printer.cfg is not needed
Be sure to check our “Knowledge Base” Category first. Most relevant items, e.g. error messages, are covered there

Describe your issue:

…

I want to remap the MCU fan pin to be an Aux fan (so i can control this thing

Ender 3 Auxiliary fan

and then i just want to wire in a permanently on fan for the MCU via some other pin on the board (it’ll prolly need to be a non 24v fan to utilize the lower voltage outputs)

But for now I’m asking how to remap a pin here is the map of the board

I want to use the FAN 1 Port.

any help on how to get started?

2

Wow. I used Chat GPT and it actually helped for once. this is what it gave me.

In Klipper, you can configure an auxiliary (AUX) fan by defining it in the printer configuration file. The process involves specifying a fan pin and creating a fan object that Klipper can control. Here’s how you can do it:

1. Identify the Fan Pin

Determine which pin on your board is connected to the AUX fan. Refer to the pinout diagram for your board (e.g., BTT SKR Mini E3 V3).

2. Update the Klipper Configuration File

Edit your printer.cfg file (or equivalent configuration file). Add a section for the AUX fan, specifying the correct pin and desired settings.

Here’s an example configuration:

ini

Copy code

[fan_generic aux_fan]
pin: <pin_name>
kick_start_time: 0.1
off_below: 0.1
cycle_time: 0.01
shutdown_speed: 0.0

Parameters:

  • pin: Replace <pin_name> with the actual pin name (e.g., PB0, PA1). Refer to your board’s documentation for the correct pin.
  • kick_start_time: Time in seconds for an initial speed boost to ensure the fan starts spinning.
  • off_below: Minimum speed (as a fraction) below which the fan is considered off.
  • cycle_time: PWM cycle time for the fan. Default is usually fine.
  • shutdown_speed: Speed to set when the controller shuts down (e.g., power off).

3. Restart Klipper

After saving your changes, restart Klipper to apply the new configuration:

bash

Copy code

sudo service klipper restart

4. Test the AUX Fan

Use the terminal in your Klipper interface (e.g., Mainsail or Fluidd) to test the fan. For example:

  • Turn the fan on at full speed:

gcode

Copy code

SET_FAN_SPEED FAN=aux_fan SPEED=1.0
  • Turn the fan off:

gcode

Copy code

SET_FAN_SPEED FAN=aux_fan SPEED=0.0

Notes:

  • If the AUX fan is temperature-controlled, you can link it to a sensor by using [temperature_fan] instead of [fan_generic].
  • Always ensure that your fan voltage matches the board’s output voltage.
3

Just in case ChaptGPT goes down, you can always RTFM:

https://www.klipper3d.org/Config_Reference.html?h=fan#fan_generic

2 Likes
4

Oh my god, I had to look that up and now I am dying laughing :grimacing:
I am with EddyMI3D on this, those abreviations and internet slang are totally over my head :rofl: :joy:

3 Likes