Guide: Alexa Octoprint Integration & Coaster

thingiverse

This guide is designed to walk you through the process of adding smart home controller support to a Raspberry Pi and integrating that support with Octoprint. This example focuses on controlling the power for an Ender 3, but it should be easily adaptable for other items like lights and fans. What's the Coaster About? It seemed morally wrong to click "Publish a Thing" without actually having something to share. Disclaimer Please note that this project involves some basic electrical work, even if most of that is low-voltage DC. You still need to exercise caution. If you are not comfortable with basic skills like soldering or reading a volt meter, it might be time to stop. Deliverables When complete, you will be able to turn your printer or lights on and off using your smart home controller, as well as control the USB ports to prevent powering the motherboard LCD while the relay is off. Hardware Setup First, let's talk about the hardware setup. You'll need a Raspberry Pi, a relay module, a buck converter (if equipped), and some wire. The wiring diagram for the relay can be found in the resources section below. Here are the steps to follow: 1. Connect the relay module to the raspberry pi. 2. Connect the buck converter to the raspberry pi (if equipped). 3. Connect the relay module to the printer's PSU. 4. Connect the USB ports to the motherboard LCD. Software Setup Now that we have the hardware setup, let's move on to the software setup. You'll need to install Node.js and the node-fauxmo library. The installation instructions can be found in the resources section below. Once you've installed the necessary software, you'll need to create a script to control the relay module. This script will call the emulation script mentioned above. Here are the steps to follow: 1. Create a new file called powerPrinter.py. 2. Add the following code to the file: ``` import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) relayPin = 17 GPIO.setup(relayPin, GPIO.OUT) def turnOn(): GPIO.output(relayPin, True) def turnOff(): GPIO.output(relayPin, False) ``` 3. Save the file and make it executable. 4. Create a new file called powerPrinter (controller with additional logic). 5. Add the following code to the file: ``` import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) relayPin = 17 GPIO.setup(relayPin, GPIO.OUT) def turnOn(): GPIO.output(relayPin, True) def turnOff(): GPIO.output(relayPin, False) def powerUSBports(on): # Code to control the USB ports goes here ``` 6. Save the file and make it executable. Emulation The emulation script is responsible for interacting with your smart home controller. This script calls the control script mentioned above. Here are the steps to follow: 1. Create a new file called fauxMo.js. 2. Add the following code to the file: ``` const Fauxmo = require('node-fauxmo'); const devices = [ { name: 'Printer', pin: 17, }, ]; Fauxmo.on('deviceStateChange', (device, state) => { if (state === 'on') { turnOn(); } else if (state === 'off') { turnOff(); } }); ``` 3. Save the file and make it executable. Boot The final script is responsible for starting the emulation script at boot time. This script uses a cron job to ensure that the emulation script is started every time the raspberry pi boots up. Here are the steps to follow: 1. Create a new file called start_emulation.sh. 2. Add the following code to the file: ``` #!/bin/bash # Start the emulation script node fauxMo.js & ``` 3. Save the file and make it executable. 4. Add a cron job to start the emulation script at boot time. Resources * Git Hub Library (this writeup) * https://github.com/NHiggs/OctoFauxmo * Git Hub (node-fauxmo) * https://github.com/lspiehler/node-fauxmo#readme