Many successful candy deliveries @Lego World Utrecht 2014

At Lego World in Utrecht, our two trains have delivered many candy sweets to the visitors.

We experienced some problems when starting the layout:

  • A timeout error in the EV3 code. It seems that deleting a file and immediately writing again to the same file (this may sound stupid, but files can only be written in Append mode and that’s not what we need for our WiFi protocol) causes sometimes a race condition. Adding one second waiting time between the two actions, solved the problem. We had to implement this solution on all seven EV3 programs.
  • Lots of WiFi interference from others. Our router wasn’t password protected (since it wasn’t connected to the Internet, we thought that this wouldn’t be a problem). We suspect that (smart)phones are constantly seeking for (free) WiFi and therefor make connection to our router. After we made the router password protected, we had no problems anymore with randomly disconnected bricks.
  • One of our newest EV3 went dead: the ‘Back’ button didn’t function anymore. Fortunately, I was able to borrow an EV3 brick of Martyn Boogaarts of Mindstorms.

EV3 went dead

When we solved these and some more little problems, the train has run for almost 3.5 days without any major situations. The Sioux.NET on Track team look back with great pleasure to the last year of building and showing the results at Lego World 2014.

See you all next year in 2015.


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