IoT Moist

The server software for an Internet of Things Humidifier written in Ruby with Sinatra.

What

At a hardware hackathon I modified a USB powered desk humidifier so that I could read the LED and control power from a Raspberry Pi. This is the code that runs it.

Compiling & Running

This project is divided into two components: the Control server, which runs on the Raspberry Pi, and the Web server, which serves the HTTP pages and API. The two parts communicate via messages passed over RabbitMQ.

Preliminary

This project relies on having an AMPQ server set up. I'm using https://www.rabbitmq.com/ personally. Copy settings.sample.yml to settings.yml and edit it to contain the details of your AMPQ server. The project needs to be able to declare and access the exchanges:

• humidifier-state
• humidifier-command

The Control Server

All of the relevant files are in the directory /control.

IMPORTANT: Edit control.rb and setup.sh and define the proper pins. If you mess this up something could get damaged!

Install Ruby 2.3.1, then:

bundle install

Create a gpio group on the server, then add your current user to it. Set up all the pins (needs to be done every reboot):

sudo ./setup.sh

Finally, run the control server:

ruby moist.rb

Web server

All of the relevant files are in the directory /webserver.

Install Ruby 2.3.1, then prepare the required gems:

bundle install

Either set the server up to run in a Rack-compatible configuration (recommended), or run the server standalone with:

ruby webserver.rb

API

GET /:
Shows a user-friendly webpage

GET /humidifier:
Get the status of the LEDs as JSON

POST /humidifier:
Turn the humidifier on or off. Takes a JSON object in the body with "power" set to true or false.