Thymio II is interactive, sensor-heavy, adaptable and affordable. The mobile robot, which goes for a quarter of the cost of a Roomba ($107), is also LEGO compatible and easy to program with EPFL’s Aseba software.
Thymio II robot’s dimensions are only 11 x 11 x 5 cm (4.3 x 4.3 x 2 inches), but its small size didn’t prevent its developers to equip it with a large number of sensors. It is powered by a rechargeable Li-Po battery, and it uses 2 wheels with speed control in order to move. The robot can be recharged as well as programmed via micro-USB connector at its back side.
It is equipped with 7 proximity sensors (5 at front and 2 at the back) which enable it to detect close objects, 2 ground-directed sensors which enable it to detect the edge of a table or a line to follow, 3-axis accelerometer which enables it to measure acceleration, detect impacts and indicate gravity, a microphone that can record sound to a memory card, and an electronic thermometer used as a temperature sensor.
“We worked really hard on the hardware”, said Francesco Mondada, Senior Scientist in EPFL’s Robotics Systems Laboratory who led the development. “Each sensor is associated with a colored LED, which allows the kids to visualize the activation of the sensors during a specific maneuver.”
o II has 39 LED used to visualize sensors and interaction. The robot also has a speaker meant for audio interaction. On its top, the robot has an indicator of its battery state, bumps used to hold LEGO, and 5 capacitive touch buttons with activity display and ON/OFF function. After turning on the Thymio II, users can set the robot to work in one of the preprogrammed modes which are distinguished by its behavior and the color robot emits when it is in particular mode.
In friendly mode the robot emits green color and it follows the object in front of it. Explorer mode (yellow color) makes the robot explore the environment while avoiding obstacle. Red color indicates the robot is in the fearful mode in which it detects shocks and free falls, and shows the direction of gravity. The robot’s investigator mode, signalized by cyan color, enables it to follow a trail marked by black color. Thymio II in purple color indicates it is ready to follow instructions. When it is in this obedient mode, it can be controlled by the buttons on a remote controller.
The programming is done by Aseba – a simple open source language similar to Matlab. Aseba is available for modification or downloading over the Internet.
Aside from introducing children to the appeal of technology and robotics, Thymio’s price point makes it an ideal platform for the physics classroom as the robot’s interactivity incorporates principles such as gravity, the properties of light and temperature.