Turn off hotend fan when printer is idle

[spuder]

Thanks for making such a great product.

As a customer I love to have my 3d printers on standby so I can print without having to walk into another room.
However having the printer fan constantly running is unpleasant, especially because none of my other printers make noise while idle.

Please update the firmware so that if the hotend is cold, the fan turns off

Research

(Credit to kivinen in the discord for finding the following)

1. The hotend fan has 3 wires. Confirmed that there is RPM control to keep fan running at consistent speed. (Opposed to being tied directly to the PSU).
2. The hotend fan is named FAN3 on the pcb

3. anker_nozzel_board.cpp has the following functions and commands.

anker_nozzle_board_get_fan_info	M3004
anker_nozzle_board_set_fan_pwm_num	M3005 value
anker_nozzle_board_set_fan_pwm	M3006 num adc pwm

This seems like the most likely location to configure the fan speed, however without the ability to send gcode with ponterface/octoprint I've been unsuccessful in verifying this theory.

4. gcode.pp line 111 passes M3001, M3002, M3003, M3004, M3005, and M3009 to the nozzle board.

5. M3001_M3009.cpp sends commands to nozzle board

6. Configuration_adv.h only has 1 enabled fan. This most likely is not the hotend fan

[spuder]

Related Discord feature requests

• Please have fans turn off when idle
• Standby mode for fans and screen
• Fans slow down / stop after print has completed