After a few iterations of the tube and wheel idea, our cherry dispenser is perfected. We initially tried a model magic version of the wheel, which wasn’t precise enough:
After some fooling around, we finally got to our final design. We cut up sheets of plastic and used a glue gun to assemble a water-wheel type of mechanism around a LEGO Wheel Hub:
The plastic sheet in front is to stop more than one cherry from falling out at a time. The red stuff you see around the clear plastic tube is tissue paper, to cushion the tube and hold it gently in place in its LEGO cage.
Our first sundae!!!!!!! It’s not perfect, but it tastes pretty good.
We’ve spent most of the day making sundaes for everyone! These run throughs have led us to make many small adjustments to the Robo-Sundae Creator. We ran into a small problem when one customer wanted no cherries. Our program, however, didn’t recognize that correctly and gave him…infinity cherries. We’d had it set so the cherry dispenser would continue going until the number of times it had dispensed matched the number entered by the customer: sounds good, right? But the counter started at 1, so if a customer entered 0, it would never get there. It was a relatively easy fix. Here are all of our final programs:
You may also have noticed that we ended up laminating our paper track—it only took us two significant spills (and subsequent ripping out and replacing of ruined paper) to figure that one out.
So what’s next? This is our last blog entry. The design, construction and programming process is complete! We have created a series of robots that work together wirelessly to produce a customized ice-cream sundae. If ever we feel compelled to return to the project, we could always add more topping stations (candy, cookie crumbles, different syrups etc) or automate even more of the sundae making process (scooping ice cream, spoon dispensing, etc). We’ve learned a lot while tackling design issues, and remembered the struggles and satisfactions of tackling a truly awesome problem. Before we tackle another, we are working on turning our work into a comprehensive feature that will hopefully inspire others to tackle their own “Process Bot” projects. Be on the lookout on legoengineering.com for the final product!