Coin Operated Micro:bit Machines

As part of our computational contraptions online tinkering course we’re exploring the connections between digital tools like the micro:bit and the automata made by the artists of Cabaret Mechanical Theater. For much of the course we were inspired by the playful and whimsical machines of Tim Hunkin and we created a coin switch project directly inspired by the Under the Pier Show and Novelty Automation.

The arcade machines provide a lot of great ideas to projects, but we are also really grateful that Tim works so hard to share his process online as well. The group got to see that the PLC machines that he uses are a bit more complicated and robust than the micro:bit but actually remarkably similar in functionality. And he shows how rough versions of the coin switches can be made with simple everyday materials.

On the third week of the CMT course, we wanted to start exploring inputs for the micro:bit and the coin acceptors seemed to be a great way to connect to the CMT artists. For a first experiment, we just connected a simple cardboard and foil switch to our micro:bit and made a basic program.

Next, I showed a couple examples of different orientations of a coin switch from a horizontal slide to a more sleek wall mounted method.

In my pre-workshop prototyping I even created a version with a servo motor that knocked the coin into a little box after showing a little animation. This made it possible (in theory) to insert a coin over and over and collect the proceeds from the mechanism.

After the session, workshop participants created their own version of the coin switches. It was so cool to see so many different solutions to the same challenge. In the online workshop we’re constantly trying to find the balance between working with physical mechanisms, coding and electronics and this prompt seemed to hit a sweet spot for all three areas. I’m looking forward to taking this idea further in our next round of CMT workshops.