The 2 Euros Machine

In January Kolle Rebbe, a german agency, asked if I could help them with their project. The idea was to have an interactive ad poster to collect money for Misereor, a german relief organization. The campaign is named “Mit 2€ viel bewegen”, which means something like “getting things moving with 2€”. You would donate a 2 Euro coin and the coin would travel through the poster, a bit like a marble in a marble machine. On the way to the bottom, the coin would trigger all kind of animations to show, what the money would be used for. Very cool idea!

At one point a picture should be taken and then displayed on a small display, and if the donor agrees, the picture would be uploaded to a Facebook page. That would be my task to solve.

We decided to use a Mac Mini as host, a webcam and an external 7″ USB-display. I wrote the software in Processing, mostly because it had built-in video capture capabilities. The upload was done using Apache HTTPClient and a 3G stick. Below the display we had two buttons, one for upload, one for don’t. The model-maker used a USB-keypad, which he broke up and simply soldered the buttons to two of the keys on the keypad. Clever!

The software is rather simple. It has a state machine that gets triggered by photoelectric barriers or button presses. The first barrier would trigger the picture, the second would display the picture on the display. The yes-button would trigger the facebook upload then switch to the initial state again.

As the whole ad poster would stand for a month or longer at the airport here in Hamburg, I used Dropbox as deployment method. I thought, it would be smart to have something, that would automatically sync a folder, if I had to update something of the software. Also I added a logging mechanism (log4j) to the Processing sketch to be able to tell, if the sketch is still running or not. The log file would be on the dropbox folder as well. As it turned out, after a couple of updates, the syncing just stops. Maybe Dropbox decided to cancel syncing if changes to a file are too rapidly, I haven’t checked. We had the 3G stick fail a couple of times, so that the internet connection was lost, but despite that, everything else worked pretty well.

Here are some pictures of the first rough prototype, used to test all dimensions and mechanics.

Here is another picture, showing the final result, installed at the airport in Hamburg.

Seeing it live is really cool. It looks much better as on the video. Also the craftsmanship that was used to build this thing is awesome. Hat tip to the great model-maker guys at Thomas Beecken and to the fantastic illustrators (whose name I forgot, sorry).
Thanks Kolle Rebbe for asking me.