Introduction

This is my Bachelor Degree final project and also my first contact with robotics. Basically, consists in two robots, one can be controlled by a human and the other will follow the first. Our aim in this project was to fuse Lego Mindstorm with the famous Nintendo Wii Remote to make use of its sensors.

Objective

Design and build two robots. The very first (Robot A) is controlled with a Wiimote  and incorporates a 4-led board. The second robot (Robot B) is completely autonomous and its mission is to follow the first.

Parts

The robots are built with the construction kit Lego Mindstorm. Both robots make use of the Wiimote in different ways, and additionally the first robot includes a 4-led board in its rear. Due to the problems I had to connect the wiimote directly with the Lego Mindstorm, a computer is used as “external brain”. So, the wiimote and the Lego Mindstorm is connected to the computer through Bluetooth, and the computer executes all the logic.

Robot A

RobotA-2 This robots is not autonomous. It is the Wiimote pad who determines the direction to take. It was a version controlled by the Wiimote accelerometer, but it was hard to control. In the picture can be appreciated a 4-led board installed in its rear. These led are detected by the second robot to know what direction have to be taken.

Robot B

RobotB-1Opposite to the Robot A, this robot is fully autonomous. A wiimote is installed “inside” it. The infrared wiimote camera is used to detect the Robot A 4-led board. If the led are detected, the robot determines the direction and the velocity, if not, it starts a search process

Interface

InterfaceAs the logic is all executed into the computer, an interface was developed to know the robot status as well to stablish the different connections.

It make easier to know where are the led into the camera sensor, the battery status and so on.

Experiments

Along the project a great number of experiments were executed. As my first contact with Lego Mindstorm and Wiimote, I had to test a lot of libraries and different firmwares for Lego Mindstorm. Finally, the leJos firmware were selected as candidate to substitute to the original Lego firmware. To control the Wiimote the library selected was CWiid.

I do not want to bore you with small experiments, take a look to this youtube playlist to know about the different experiments

After a lot of effort and some experiments, finally the Robot B was able to follow to the Robot A, here the prof:

Conclusions

As first contact with the robotics it was a complete success. The project was qualified with honours and was the start point for further work related with the robotics. If you are interested in the project day-to-day project take a look to the Nine Years blog (In Spanish)

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