Bette183114776: Updating to match new version of source page

2020-09-15T16:31:26Z

Updating to match new version of source page

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=== Introduction ===

Often it is important to stop the robot if it sees an obstacle. The ultrasonic (or infrared) sensor is a suitable tool for that.

=== Robot ===

Any robot (with tires or treads, perhaps walking robots too) will work.

=== Sensors ===

The ultrasonic (distance) sensor is used. The sensor is attached to port number 4.

=== Example Videos ===

<youtube>r8FcMB5bwhA</youtube>

=== Theory ===

The ultrasonic sensor is a sonar radar that works similar to that of the bats. You should check the performance of the sensor in advance, specially if it is not working properly. A hand might be a not optimal device for checking -- you should use something more solid, eg. plastic of cardboard. The maximum working distance is about 2 meters, and the smallest distance is about 10 cm.

=== Example Code ===

[[File:Stop10cm.png|thumb|The code that stops the robot when in a proximity of a wall.]]

=== Exercises ===

* Make the robot speed dependent on the distance to the wall, e.g. by using a formula speed = distance.
* Use the ideas shown in previous part (Following a Line) to follow the wall at 10 cm apart.
* Follow a line (previous part) until the robot finds a wall at 10 cm apart from the wall.
* If you have multiple robots, make the robots follow a line and each others, not colliding with the robot in front of.
* Use the ultrasonic sensor to listen if there is other robots using ultrasonic sensors.

[[File:Ultrasonic.png|| Listen]]

This course is supported by [https://meet-and-code.org/ Meet and Code]. The course is made in collaboration with [http://www.fllsuomi.org/ Robotiikka- ja tiedekasvatus ry].
[[File:MeetAndcodeLogo.png|thumb]]

[[Meet_and_Code_2020_I:_Ev3-G | Back to Meet and Code 2020 I: Ev3-G]]

Stop at given length from the wall/en - Revision history

Bette183114776: Updating to match new version of source page