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A place for all things related to ye olde Spark Thermostat Hackathon
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app added sidetiq to do the background polling to access actual temperature Jan 17, 2014
doc Add MIT license and final readme tweak Jan 17, 2014
hardware added schematics and cad files Jan 20, 2014
public root#index and root route route added to rails app Jan 16, 2014
spec http://localhost:5000/actual_temp_readings.json and http://localhost:… Jan 17, 2014
vendor added moment.js and flot.js and fixed exported env vars in start_serv… Jan 16, 2014
Gemfile added sidetiq to do the background polling to access actual temperature Jan 17, 2014
Rakefile Add a Rails skeleton Jan 16, 2014 Add a Rails skeleton Jan 16, 2014

Spark Open Source Thermostat

This repo contains all of the software goodies produced in a 18-hour Spark Team Hackaton described in detail on the Spark Blog.


The thermostat display is composed of 3 Adafruit Mini 8x8 LED Matrix boards.

The temperature and humidity are sensed using a Honeywell HIH6131-021-001.

These are all controlled by the Spark Core using a common I2C bus where pin D0 is SDA and pin D1 is SCL. The displays (from left to right) are on I2C addresses 0x70, 0x71, and 0x72.


The details of the circuit design and implementation can be viewed via EAGLE (a free program for PCB design, downloadable here). The eagle file is in the hardware/EAGLE folder.

Physical Design

3D model sketch-up files are available in hardware/folder. If you're viewing this on GitHub (and using a modern browser), you can view a 3D rendering of it too.


To build firmware for this product, you'll first need to be able to build Spark Core firmware by following the instructions shown here.

Once you have that working, you can simply copy all of the files from /firmware in this repo into core-firmware/src and run make again to build. (i.e. cp thermostat/firmware/* core-firmware/src)

Alternatively, you could use the Spark Web IDE.

Server Setup

The server components are:

  • a Rails 3.2 app
  • Sidekiq and Redis for background job processing

Development was done on OS X.


  • Ruby 2.0 (recommended to use rvm, rbenv, chruby, or other ruby version manager) (this app is ruby-2.0.0-p247)
  • bundler: gem install bundler
  • Install redis: brew install redis
  • Install foreman: download package from here
  • bundle install

Run Locally

In one terminal:

redis-server /usr/local/etc/redis.conf

(following instructions from homebrew install)

In another terminal:

bash script/
  • Note: You might need to change the SPARK_CORE_DEVICE_ID and SPARK_CORE_ACCESS_TOKEN env vars in this .sh file for this to work.

Hit http://localhost:5000 in a browser

Dev tips

You can put binding.pry pretty much anywhere in the code to bring up an interative debuging console. Then hit a brower make or whatever, and in the terminal where the script ran, you can type commands (like a var name) and see their value, etc.

The "SQLite Professional Read-Only" OS X app is a nice free app to look at the data the app is generating in real time.

When developing, it's nice to be able to destroy everything and start fresh when you are hacking:

bash script/

What's Next?

Get your hack on, :), have fun. If you do something cool with anything in here, consider sharing it on the community site.

Check out some of these other related open thermostat projects:

If you want to list your cool open thermostat project here, issue a pull request.

If your are interested in continuing the effort to build an easy-to-build-and-install Spark powered open-source thermostat, please contact or create a GitHub issue. Though we'd love to do this ourselves, we don't currently have the bandwidth here at Spark. Hope to hear from you.

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