Geek competition: how we did it (part 1)

As many of you will remember, we are now in the midst of a raffle . Briefly recall what we are talking about. Some time ago we set about the idea of ​​coming up with something interesting for Habr, timed to the Day of the programmer. As a result of long discussions, we had the idea to hold a prize draw, but not a classic and boring, but an unusual and geeky one. In the course of experiments and disputes, a clever installation was born for printing the tickets of participants of the draw and ... measuring the weight of the total mass of tickets. Arduino, sensors, cameras, aluminum profiles, plexiglass, some engineering savvy and a lot of obscenities - who would have thought that all this would make an interesting project?

According to the rules of the rally, October 25 is the last day when all late ones can still take part. We remind you that for this you need to have an account on Habré and click on one single button on the project page. Accounts can be any, both read only, and with an invite. And the ceremony of determining the winners will take place on October 31, on Halloween. But we will inform you about this later.
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We have prepared a video in which you will learn firsthand about how we invented and created the installation, which has been working around the clock for a month on the project page.