Robot App Store

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Lego Wall tracking robotRobot-App Page

Relevant Robots:
  • LEGO - Mindstorms NXT 2.0
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Robot App™ Description

This app locates a wall and then drive alongside the wall in parallel. The idea is that the robot uses the radar to compute the angle to the wall, and then adjusts its steering to set the wheels pointing parallel to the wall. Of course the robot has to take periodic measurements to ensure that it is not deviating from the chosen course!

Developer: Mark C

LEGO®is a trademark of the LEGO Group of companies which does not sponsor, authorize or endorse this app. This app does not feature any of LEGO's copyrighted or trademarked material, and is in accordance with their fair use guidelines.

Installation Instructions

Delivered as:

Robot-C code - Click the Download button above to see it.


Robot App Requirements



Other requirements:

Usage Instructions

The basic idea is to take three radar measurements facing the wall and from the distances returned determine whether the robot is parallel to the wall, or turned to the left or right relative to the wall face. For this we’ll use some trigonometry to solve for the angle between the robot and the wall.
First off, the angle we are looking for is given as the letter A in the figure below. If the robot is facing the wall straight on then A = 90 degrees.

To solve for A I used the Law of Cosines and the Law of Sines using the measurements obtained from the DISt-Nx sensor. To begin, we measure the distances from the robot face to the wall.

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