ROBOTMAK3RS Blog

A Spirograph is a geometric drawing tool that produces roulette curves. Christoph Bartneck has created a cool implementation with LEGO © MINDSTORMS EV3:

This NXT Area and Volume Calculator is a little math exercise for your NXT, which gets it to act like an electronic "rolling tape" measuring device, to calculate length, area, and volume in both metric and English units. As some of you may know, the new NXT-G 2.0 software from LEGO Education has added support for "floating point" (non-integer decimal numbers such as 12.3) numbers and math. I was pondering what this meant for users of the existing NXT-G 1.x software, which only supports integer numbers and integer math. So I decided to cook up a little exercise to do some math that could benefit from floating point, but still done the integer way, so the program for this project will work in either NXT-G 1.X or 2.0. For those interested, here is a brief summary of some of the issues. A basic technique of integer math is to pay attention to the order of operations and store results scaled up in precision if necessary. For example, if there are 2.54 cm per inch, how ...

A group of students at the Institute of Imaging and Computer Vision of the Technical University of Aachen , Germany, has developed a toolbox that allows for controlling MINDSTORMS NXT robots over MATLAB® , a numerical computing environment and programming language widely used in industry and academia. The toolbox, a result of a Project in Electrical Engineering and Information Technology called MATLAB meets LEGO Mindstorms , "enables you to combine robot applications with complex mathematical operations and visualizations within MATLAB . This toolbox opens unlimited possibilities to provide the robots artifical intelligence and other improvements using the manifold MATLAB features and calculations for digital signal processing ", as the project's web site states. The toolbox is licensed as OpenSource Software as part of the GNU GPL (GNU General Public License) and can be downloaded for free .

I run workshops with students all the time, and one of the first activities I do, is make them get their robot to drive forward 500mm. For the younger kids it's mainly trial and error, for the older kids I get them to calculate circumference and mathematically work it out. But I was finding that the theory wasn't quite matching up to real life. I have in the past explained that every robot is subtly different. (this also helps to stop kids running to another computer and stealing other students values) So I sat down and worked through the math to have a look at why my students were getting what I considered fairly different numbers for the same 500mm. (warning, basic maths ahead) If we take the diameter of the NXT wheels as 56mm (as written on the side) we get a circumference of: c = pi * d c = 3.14 * 56 c = 175.84 To go 500mm, we divide 500 by the circumference x = 500 / 175.84 x = 2.8435 rotations x = 1024 degrees But I was finding that some kids needed more than this. Le...