Cloud cup: a multiplayer set of mini games for web and Android

I’m glad to present the work of a week-long hackathon I did last November with three other googlers.

I’ve been having for a long time the idea of a real time game using phones as controller and a big screen as the main game screen. You may recall a previous blog post about a first prototype. A few years later, I could pitch the idea at an internal hackathon and gather a team around the concept. While I initially wanted to build a dancing game, I realized that this was already done, so we decided to go towards mini games, an idea very compatible with a hackathon timeframe.

Realizing after a day that we would not be able to have a reliable and scalable real time architecture and a fun game after just five days using regular backend technologies, we decided to focus on the game itself and to use Firebase to handle the real time and backend parts of our system. It allowed us to get familiar with this very interesting technology. I already used Parse in the past, while they both fall into the Backend as a Service (MBaaS) category, I could notice with pleasure that Firebase was able to perform as well as Parse for the regular MBaaS features (and even better to my taste, by providing an Angukar SDK) but that it also provides impressive real time capabilities.

After a single day, we had a functional prototype of our game: Android phones were interacting in real time with an Angular application in a “Shake” game. The next three days were spent creating other mini games and streamlining the game mechanism.

And we won the Fun category!

While the hackathon was internal, it was not a problem at all for Google to let us open source and release our work to the public. You can find the sources on GitHub: Android and Web. Firebase showcased the project on its official blog.

Try it now: Install the Android app, and visit to start a game.

I hope you like it.


I’ve been hacking on a little project during the summer. The idea is to use the phone as a remote controller for a game displaying on a screen. I’m building a dance game, where the players’ goal is to follow a dance seen live in a video.

I’m using the accelerometers of the phone to record the movement of the players. Then I compare this to the reference movement of this video. If the movement match, the player earn points. The best dancer win at the end of the game.
Technically, the main challenges are the processing of the accelerometer data and communicating in real time.

Accelerometer data from the phone: I could use the native APIs and build a native app, but Phonegap is providing an accelerometer API, so I could build my app once and use it on many platforms.

Data comparison: I have to use well thinked descriptors to compare the recorded data to the reference. I will start by detecting the “bumps”, their direction and their amplitude.

Live communication: I’m using some real time technology to make all the device communicating with a server in real time: my choice is to use node.js and the library (and to ideally use web sockets).

Data store: the library of dances will be stored in a no-SQL database. My choice is to use mongoDB.

Record a dance: one last challenge is to record the reference dance for a given video. I will try to use some simple machine learning algorithms to extract the reference from a set of records.

You can follow the development on my github.