Activity: Stop On Colour Change

ActivitiesAll

3 June

Program the rover to keep moving forward until it detects a change of floor colour with the colour sensors. Once it detects this colour, stop the rover.

  Relevant Coding Skills

    Iteration    
  
   Relevant Rover Concepts
 
    Colour    
  
    Motors

Activity Demonstration

Setup

For this exercise we recommend a strip of tape stuck to the floor that contrasts the floor colour. It doesn't have to be tape, all that matters is there is a clear change in colour for the rover to detect. An alternative solution is to use a piece of coloured paper.

Your solutions should work no matter how far from the tape the rover starts. Make sure to test the same code from multiple starting positions.

Here’s Our Approach

Stage 1

First we need the rover to drive forward towards a change in colour. We tell the rover to move forward with a start moving motor block.

Stage 2

As the rover drives forward, we need to be constantly checking the colour sensor. Use a repeat until loop block where the condition is set to detect the desired colour. Our code is looking for the brightness of the white tape.

Stage 3

The rover will keep checking the colour sensor in the loop block until the condition is true. After the repeat we stop all motors.

Note

If the simple colour sensor blocks aren’t working we may need to use a different comparison block to check more detailed readings from the sensor. Use the rover sensor view to identify the one that will work best for you.