Tea serving EV3 robot (Karakuri ningyō)

EV3 Biped robot that serves tea, as ancient japanese karakuri

September 2013: I’ve always been fascinated by wind-up toys, and even more by the advanced wind-up automata (plural of automaton) from the 17th Century. The clock makers Jacquet Droz and Maillardet made breath-taking automata that could draw write and even play instruments (that inspired LEGONARDO). Meanwhile, in Japan, wind-up puppets were created for home entertainment, or to be used in theaters. Their original name is Karakuri ningyō, that can be translated as “mechanical doll”. Among the small-sized Zashiki Karakuri, the tea serving one is the most famous. Such automaton has a mechanism that makes it go forward as soon as a cup is placed on the tray it is holding. It proceeds forward, and just before turning, it bows. That’s the signal to pick up the cup. As soon as you pick up the cup to drink, it stops. When you’re done with the tea, you place the cup back on the tray, and the automata finishes turning, and comes back to the point where it started. The timing for travelling, bowing and turning is controlled by cams. If you want to build your own Karakuri doll, there’s even a (freaking expensive) kit.

Inspired by that simple yet very effective Japanese automaton, I designed my tea serving robot. The design of the legs is based on the LEGO MINDSTORMS NXT Alpharex version 2.0. I adapted the design to build it using only the parts from the LEGO Education EV3 Core set 45544. I reproduced the working of the original automaton, but modifying the behavior a bit. A Color Sensor detects the presence of the cup (the tire), while two touch sensors are used to reset the legs at startup. The Medium Motor makes the head bow, while the Ultrasonic sensor is used just as decoration. Using the EV3 Software Sound Editor, I made the tea serving robot speak Japanese. It should say “I’m awating for the cup”, “Please refill the cup”, “Enjoy the tea”, “It’s a pleasure to serve you”, but I’m not 100% sure of the outcome.