The Thymio robots in the "Mécamorphose" show

Introduction

« Mécamorphose » is a show designed and presented by the music school of Rolle (Switzerland) to celebrate their 40th anniversary. This show is, according to its creators, "between a musical and a mechanical ballet." This show was presented in the old cellars of Gilly-Bursinel in late November 2013.

This page presents a brief summary of the work done for this show from the robotics point of view. The goal was to animate some elements of the set of the play and the pre-show that the public could discover an hour before the start of the play.

The play

The play tells the story of a great inventor, called professor "D", in love with a dancer, fascinated by her grace, but socially incapable of managing this relationship. His creativity and desperate love will push him toward increasingly dangerous ideas on how to become the ideal man for a dancer …

Engineering behind the scene

Two students from EPFL, Bendicht Grossniklaus and Igor Ayrton, took care of the decor and robotic "interventions". The Thymio robot was chosen for its ease of use and for the possibilities of colour display. Given the limited time available and the lack of experience in robotic shows, Thymio proved to be a suitable medium for rapid implementation of persuasive effects. 30 Thymios were available for the show. Half were used on stage and half for the pre-show.
Other robotic effects were also achieved by modifying existing objects such as desk lamps, elements of existing robots and industrial robots. The Arduino platform was used to control various motors and actuators.

Using Thymio: show and pre-show

Show

The room, created in the old cellars of Gilly-Bursinel consists of a stage, a large orchestra pit and rows of seats for the spectators. The stage is in two parts: a "living room" and a "research lab," where Professor "D" performs his experiments. This last part is full of robots.

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Laboratory shelves

On the laboratory shelves, several Thymios change colours randomly so as to give the impression of movement at the back of the stage. The values for the RGB LEDs are incremented or decremented by relatively small values, the colours thus changing gradually.

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Laboratory tables

Several Thymios move around on different tables without falling (detection of the edges of the tables and of obstacles).

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Ceiling

A spider descends over the orchestra in the middle of the show. To build the spider, a Thymio was painted entirely in black, only two circles and a cross at the back were left uncovered. The RGB LEDs flash blue to attract the attention of the public, while the spider descends from the ceiling.

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A simple Thymio without wheels was used in a similar way during the transformation scene of the professor, blinking red.

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A double winch and its control were designed to move up and down both the Thymios hanging from the ceiling. They need to function independently because they are not active in the same scenes.

Ground

Several Thymios were programmed to move around on the ground, turning and flashing their LEDs. They were finally removed from the final version of the show because they interfered with the actors.
We then used them for the pre-show.

Pre-show

Before the show the audience is guided through the infrastructure of the old cellars transformed into a place of music and robotics. The guide introduces the visitors to the crazy world of Professor "D".

Musicians

The Thymio plays 5 tracks of a song, at the end of each track it stops and waits so that the musician can play an answer (i.e. playing his part on his instrument). To cause Thymio to play the next track, the musician has to pass his foot in front of one of the IR sensors. It is also possible to select the track manually or put the robot in waiting mode with the buttons. The LED circle displays which track is currently playing or has been previously played.

Walk

Several Thymios move around in the old wine tanks changing direction and colour randomly. When they encounter a wall or receive a shock, they reverse briefly and change direction.

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Musicians playing together with Thymio in the old wine tanks:

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Remote control

The operator has the option of activating Thymio remotely using a remote control. This is necessary since the Thymio must be inactive during certain scenes. The two suspended Thymios are also equipped with this feature.

Problems and improvements

Interaction with actors

One of the basic ideas was to have a dozen robots that would move randomly on stage, avoiding the actors. The first problem was the very uneven floor of the stage, so that the Thymios got stuck too often. The second problem was that the Thymios were too slow to effectively avoid the actors.

Edge of the table

We noticed that when Thymio reaches the edge of a table at a small angle, the outside wheel can pass the edge before the Thymio detects it. The Thymio does not fall but remains stuck.

Floor

As on the stage, the floor of the wine tanks was very irregular with many holes. The Thymios often remained stuck. A first solution was to adjust the sliding contact on the surface to allow passing over bigger obstacles. But it was not enough. We added shock detection for when they get stuck in a hole, making them then move backwards. Unfortunately they still get stuck periodically. Obviously they are not designed for this kind of surface.

Conclusion

Bendicht Grossniklaus and Igor Ayrton enjoyed this experience and learned a lot. For both it was a discovery and a pleasure to be able to participate in this adventure. This experience helped them to realize how much time this takes, especially with very limited resources. They also appreciated the Thymio programming environment, particularly efficient for making last minute changes.

The Thymios charging after a performance:

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