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For our next project we’re going to build a robot that makes a cup of chocolate milk by mixing together chocolate syrup and regular milk. It’s silly, of course—who needs such a thing? Still, it’s a great opportunity to expand our knowledge of Lego robotics and to introduce a couple of new tools. Plus, everyone loves a treat!
The way the robot works is that it pumps milk from its jug to a beverage cup using an aquarium pump, which pressurizes the jug and makes the milk to squirt out through an outlet tube, which conveniently dispenses into a glass. While the pump moves the milk, a second assembly squeezes a 6-oz. bottle of chocolate syrup while a stirring assembly mixes up the drink. All of this happens at the touch of the button.
This is the most complicated project in the book from a mechanical standpoint. Everything from the chocolate-squirting assembly to the stirring arm went through numerous iterations, and one thing we discovered was that it was easy to make “bad” chocolate milk, but making delicious chocolate milk means a lot of tweaking. Much of it is subjective. How dark do you like your chocolate? How important is it that the mix is stirred up thoroughly? These are the questions only ...