How to declare temperature_fan for chamber exhaust, using BME680 sensor on a pico?

Basic Information:

Printer Model:
MCU / Printerboard:
Host / SBC raspberry pico usb to raspberry pi 5
klippy.log

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Describe your issue:


Hi all

i have a BME680 monitoring temp etc. It’s connected on a pico. Pico connected via usb to a pi. The BME680 is working fine and has been declared in printer.cfg.

i have added an exhaust fan via mosfet as an outpin_pin for now, working fine and has pwm control.

i would like to add the exhaust fan as a temperature_fan controlled by the BME680 temp reading.

I’m aware that the BME section needs to be commented out, which I’ve done and will be declared in the temperature_fan section.

How do i do this?

I have tried but failed…as per below

[temperature_fan exhaust_fan]
pin: pico:gpio22
cycle_time: 0.0100
hardware_pwm: false
max_power: 1
shutdown_speed: 0
sensor_type: BME280
#sensor_pin: pico 
min_temp: 0
max_temp: 60
control: watermark
max_delta: 2
target_temp: 48.0
max_speed: 1.0
min_speed: 0.0

what would be the correct way to do this?

I know the above declaration is wrong, getting an error with the above declaration that doesnt make sense to me :

pin PB6 is reserved for i2c1

Once the underlying issue is corrected, use the “RESTART”
command to reload the config and restart the host software.
Printer is halted

The only place where PB6 is declared is:

[stepper_z]
step_pin: PB6

and nowhere else. So im not sure why its giving an i2c error with the above temperature_fan config.

Once ive learned how to get that done then i’ll be adding my nevermore to the bed temp.

Any help with this will be greatly appreciated.
klippy.log (306.6 KB)

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Thank you for the assist. Will change it now.

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