FSHS Robotics C Course

Project: tips

Detecting the silver strip

To detect the silver strip, you will need to:

Get colour readings for the silver strip (RGB) for at least one sensor (more accurate with both left and right).
Set up a big loop for your program, e.g.

task main() {
    // put variables here
    int leftR, leftG, leftB;
    int rightR, rightG, rightB;

    while (1) {
        // repeatedly get the sensor values
        // repeatedly check the sensor values to see if it is silver
    }
}

Make an if statement within the big loop that checks the sensor values to see if it is silver.
When you see silver, make a sound and stop for a second.

Transitioning from silver strip detection to other code

Code likes to run from top to bottom, but you want your code to either be detecting the silver strip OR performing the search.

The easiest way to do this is to set up a flag that tells the code which task we want to do. If the flag is 1, we do strip detection, if the flag is 2 we go forward, if the flag is 3, we are done.

task main() {
    // put variables here
    int leftR, leftG, leftB;
    int rightR, rightG, rightB;

    int currentTask = 1; // our 'task' flag
                         // 1: silver strip detection
                         // 2: going forward
                         // 3: idle/stop program
    while (1) {
        if (currentTask == 1) {
            // repeatedly get the sensor values
            // repeatedly check the sensor values to see if it is silver
            if (silver) {
                // beep and wait a second
                currentTask = 2; // change task to 'go forward'
            }
        }
        else if (currentTask == 2) {
            // go forward
            if (forward enough) {
                currentTask = 3;
            }
        }
        else if (currentTask == 3) {
            // stop all motors, do nothing else
        }
    }
}