Voron Z Chain Lower mount 4pin dupont mount

This is a remix of the Z Chain Lower mount to allow a mounting point for a single PCB via a 4 pin dupont plug.

Put whatever you want in your voron to monitor the chamber near the bed. It's perfect for an i2c environmental sensor like a BME 280 temperature/humidity sensor, SGP40 VOC sensor or a mix of both - Isik's SGP40/BME280 compact PCB sensor (I'm not sponsored by Isik, I just think it's a cool idea)

The recess in the chain mount is flexible enough to take the 4 pin dupont connector and your sensor just plugs in the front.

Installation

Example

The picture posted is of a SGP40 plugged into a closed voron 2.4 chamber to monitor VOCs during printing and uses the chamber thermister and klipper modules from the Nevermore Max* to control a nevermore micro when VOC's increase. 

Github - https://github.com/nevermore3d/Nevermore_Max/tree/master/Software/Klipper

*This project is currently a work in progress 19NOV2023

Installation

• SGP40 connected to raspberry pi host on i2c.1
• Thermister or other temperature/humidity sensor (ideally) - Note the VOC sensor is very dependent on temperature and humidity; but in a closed chamber you could get away with temperature correction only and correct for change in relative humidity

Klipper modules

copy the sgp40.py and voc_algorithm.py modules into klipper/klippy/extras

cd klipper/klippy/extras
wget https://github.com/nevermore3d/Nevermore_Max/raw/master/Software/Klipper/sgp40.py
wget https://github.com/nevermore3d/Nevermore_Max/raw/master/Software/Klipper/voc_algorithm.py

Klipper config

Using Klipper's temperature_fan PID controller the sgp40.py output tricks the controller into thinking it's controlling temperature (voc) when running a nevermore activated carbon scrubber. The SGP40 sensor relies on temperature and humidity to correctly measure VOC, but with a small assumption that you printer is enclosed we can adjust humidity from an assumed initial temperature of 25C, 50% humidity using temperature alone. Ideally you should use measured humidity and temperature to correct the SGP40 VOC_algorithm.

Here's the example using temperature correction only with PID control:

printer.cfg additions:

Mainsail (as per Nevermore_Max/Software/Klipper/reeadme.md)

In order to display the full VOC sensor information in Mainsail, the following command needs to be run once in the mainsail directory:

grep -l additionalSensors * -R | xargs sed -i 's+additionalSensors=\[+additionalSensors=\["sgp40",+g'

Output

Setting the temperature_fan VOC/2 to “60” will enable fan operation when VOC increases.

gcode: 

SET_TEMPERATURE_FAN_TARGET TEMPERATURE_FAN=VOC/2 TARGET=60 ; Turn on nevermore air scrubber VOC <= 120

Enjoy :)

Added a mounting point for a dupont 4pin plug at the back of the chamber

2 Versions:

• Original Voron 2.4 remix
• Remix of Voron 2.4 CanBus Umbilical Mount