dec 02, 2023

🔗 Auto-shutdown a 3D printer with Raspberry Pi and ESPHome

One thing that I am not a fan of, is the 3d printer's fan staying on for hours after the print is finished. I know that the power consumption is not that high, but I like the feeling of waking up in the morning and finding the printer turned off and the finished print waiting for me.

This apparently simple project also introduced me to a bunch of new topics, like ESPHome, NodeRED and MQTT. Everything started with watching this fantastic video: Save Energy by automating your 3D-printer by Andreas Spiess.

I already owned a cheap 3d printer, the OG workhorse Ender 3, and I had a spare Raspberry Pi 4B so I decided to give it a try.

In my previous post, A single enclosure for the Raspberry Pi and the Ender 3 electronics, I shown how I already moved the electronics to the back of the printer, so I had the perfect spot to place the Raspberry Pi.

# Components

Raspberry Pi 4
Ender 3
2-to-1 XT60 adaptor
Sonoff Basic RF R2 v1.3
USB to Serial adapter with FTDI FT232RL chip, like this one: DSD TECH SH-U09C
Momentary switch button

Sonoff Basic RF R2 v1.3

# Install the project on Raspberry Pi

Use Raspberry Pi Imager to install on the microSD the Raspbian OS with preinstalled Octoprint

Create a new user and login by connecting with a computer in the same network to http://octopi.local.

After that you will be able to ssh into the Raspberry Pi, if you kept the default settings you can just type:

ssh octoprint@octopi.local

Download the repo from Github via https

git clone https://github.com/danieledep/raspberry-remote-shutdown.git

Go into the downloaded folder

cd raspberry-remote-shutdown/

Make the script executable

chmod +x install.sh

Run the install script

sudo ./install.sh

# Flash the Sonoff with ESPHome

Install desktop environment to use Esphome and NodeRED on the Raspberry Pi

sudo /home/octoprint/scripts/install-desktop

Set Desktop GUI to boot at startup and set the resolution at least at 1280x720px

sudo raspi-config

Install Chromium

sudo apt-get install chromium-browser --yes

Attach a screen, keyboard and mouse to the Raspberry Pi

Install the D2XX Drivers for using the FTDI chips plugged into the Raspberry Pi

Go into the project folder:

cd raspberry-remote-shutdown/

⚠️ Last time I tryed installing Esphome with pip it failed to install cryptography because of incompatible dependencies, this fixed it:
sudo pip3 install esphome cryptography==3.3.2

Start up Esphome, use sudo to have write permission for secrets.yaml

sudo esphome dashboard /config

Open Esphome web ui at octopi.local:6052

Press on Secrets to save wifi configuration

Create a project name sonoff and copy the content of sonoff.yaml into the file

Hit Save and then Install.

The first time you flash a new firmware you'll need to connect the Raspberry PI to the Sonoff via the FTDI Module wiring the pin like the following diagram.

FTDI      Sonoff

GND ----> GND
VCC ----> 3V3
TXD ----> RX
RXD ----> TX

Sonoff wiring for flashing

The first time you flash a new firmware you'll also need to keep pressed the physical button of the Sonoff.

⚠️ Newer Raspberry Pi with installed 64bit OS might need to disable temporarely the 64 bit capabilities at boot time, in order to compile the binaries due to compatibility issues with Platformio tooling. To do so edit the config.txt :
sudo nano /boot/config.txt
add to the part titled [pi4] a new line like this
[pi4]
arm_64bit=0

# Setup NodeRED and MQTT

Open NodeRED at octopi.local:1880 import our flow nodered-flow.json and click Deploy

The NodeRED flow

Finally let's enable remote access to the MQTT broker without requiring authentication. Open the configuration file

sudo nano /etc/mosquitto/mosquitto.conf

At the end of the file add these two lines:

listener 1883
allow_anonymous true

Save the file and restart Mosquitto for the changes to take effect.

sudo systemctl restart mosquitto

# Configure Octoprint

Open Octoprint, install the MQTT plugin, tick Activate event messages, and let's only keep Printing events messages enabled.
Add octopi.local as the Broker host.

⚠️ By default the MQTT plugin has the Enable retain flag option checked. This is normally the preferred choice but for our setup where the MQTT broker shut itself down multiple times from the same machine, we don't want to have our server turn on and find retained messages from the previous session.

# Notes

Since I'm running the MQTT Broker directly on the same Raspberry PI that runs Octoprint too, which effectively self-shutdown, I don't need to run the systemd service shutdown.service.

The service was used by the original author to listen for the MQTT message coming from a different server running the MQTT Broker telling the Raspberry PI running Octoprint to shutdown.

But since they both run on the same device I can simply run the Exec node from within NodeRED, which upon receiving the octoprint/shutodwn MQTT message, it launches the command sudo shutdown now to the OS.

I still have an updated version of the necessary files and NodeRED nodes in this repository, in case I wanted to change my setup in the future.

# Testing MQTT

Check the systemd services are enabled and running

systemctl list-unit-files

From terminal send MQTT messages to the NodeRED client which sends them to the Sonoff.

To turn on:

mosquitto_pub -d -t sonoff/switch/mains/command -m "on"

To turn off:

mosquitto_pub -d -t sonoff/switch/mains/command -m "off"

To turn off after 30 seconds delay:

mosquitto_pub -d -t sonoff/mains -m "off"

# Troubleshooting

To read log messages from NodeRED in real-time

node-red-log

To read Mosquitto logs file

sudo cat /var/log/mosquitto/mosquitto.log

To read NodeRED logs file

sudo cat /var/log/syslog