The AutoRoller

Close up image of the AutoRoller
Internal view featuring Arduino Leonardo, breadboard (with unused 555 timer), 9V battery, and button on far right side
Full image of the AutoRoller

Introduction

Leading up to the weekend of Roll for Hacking, I spent hours scouring my mind for ideas. I had planned on using the Java skills I had just learned over the past month to create some sort of app for dungeon masters, but I was not sure exactly what to do. As I woke up on the opening morning, I still had no plan. On a whim, I abandoned all previous ideas and pulled out my Arduino Leonardo and a box of Lego. For my first hackathon submission, I decided to pay homage to the tools and toys that introduced me to making almost a decade ago. In the past two days, I have had a fantastic time putting together the AutoRoller, and learned a lot about myself along the way.

The AutoRoller

The AutoRoller is an automatic dice rolling contraption. Dice are loaded into its scoop, a button is pressed to shake the dice, and releasing the button throws the dice into a tray for easy reading and collection. No more losing dice off the side of your table! Up to 4 dice can be rolled at once with the regular tray. In addition to the regular dice tray, I built an extended tray which allows up to 9 dice to be rolled at once.

How I built it

I started this build by drawing some sketches and gathering materials. At first, I thought I might make the scoop out of aluminum sheets; I decided to keep the entire construction in Lego to maintain a consistent appearance, and to make assembly faster.

Once I had my physical designs, I wrote some code for operating a servomotor with a button trigger. The resulting code was only about 50 lines, all written in an hour by looking at snippets of my previous work. The materials I gathered were a bunch of Lego, a small servo, a button taken from an old toy, an Arduino Leonardo, and a 9V battery and harness. I cut some wires and plugged everything together in a breadboard. As a single person working on everything, it took me about 6 hours of nonstop work to go from idea to functional prototype; a few more hours on and off were needed to get everything looking pretty for the camera.

Challenges I ran into

My main fear for the project was that the arm was going to be too heavy for the little servo. I only had one servo to work with, and I could hear it straining when holding the arm in its rest position. For this reason, I had to add a physical support under the scoop in rest position so that the servo did not need to work to keep the arm up. This solution brought with it an unexpected benefit: when the scoop bumped into the support, the dice would jump like they were really being shaken! I think this really added to the visual appeal of the AutoRoller.

What I learned

The main takeaway from this project has been the rekindling of my love for making. Until now, I could not name any personal projects that I both initiated on my own and that I would be proud to share with others. In two days, I spend hours feeling like the ten-year-old version of myself, just making something for the fun of it. My creation may not be the most innovative or the most technically challenging, but I had an amazing time making it and I feel inspired to move on to the next project.