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Cool Project: Room Explorer Bot with Mapping Functions

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ROBOTC user, Sigtrygg (forum name), recently shared a project on the ROBOTC forums that they have been working on called the NXT Room Explorer Bot with Mapping Functions. Check out the YouTube video of the robot in action …

Sigtrygg description and breakdown of the bot …

The robot is based upon a standard REM-Bot but in addition equipped with a HiTechnic gyro, HiTechnic compass sensor and an omni-wheel. First the robot moves about 360° to calibrate the compass using the gyro (thank you to Xander Soldaat for code!). Then the robot moves its sonar-head to the right, to the left and in front position to get the distances according to its position. After doing this it turns around to the wall with the minimum distance and drives in front of it until sonar sensor detected a minimum sensor distance, e.g. 20cm. Then the robot turns parallel to the wall, moves his sonar-head to the right detecting the distance to the wall and drives counter clockwise parallel to the wall balancing distance. A mapping-task records the compass and odometry data every second and calculate the polar coordinates to cartesian coordinates (x,y). The coordinates are written as “map.txt”-file. So you can use Excel or an other program to draw the path which the robot had moved. In addition to that you can follow the path at the NXT-LCD-screen. I had to choose a scale for it, so you have to suit the scale to your room size. If the robots touch sensor has detected an obstacle the robot moves back and turn left for 90 degrees and continuous his explorer-duty always running counter clockwise with wall to the right. How to expect the end of path doesn’t suit exactly to the beginning because of inaccuracies of compass and odometry measures.

Construction of the robot. The upper sensor is the compass sensor.

Construction of the robot. The upper sensor is the compass sensor.

Screenshot of Excel data-sheet

LCD Screenshot