Programming ordeal

Technical Programming
1

Hello fellow FTCers.

My name is Brian, new to FTC, this site, and robotics and general.

My team is 5264, ILITE Blue Chips, from Haymarket.

I am one of our team’s programmers, and I have a slight problem, and was hoping someone could help.

How do i set a light sensor to activate a LED light? For example, let’s say I have a ligth sensor and 2 LED lights, one red, the other blue. When the sensor picks up anything >20, I want the red light to shine. then the sensor reads <20, I want the blue sensor to go off.
How could I program this in ROBOTC?

(Note: this isn’t the exact scenario I’m in, but it’s very similar)

2

Within main() you’d have something like this:

while(robot is running) {
    if(sensor value > 20) {
        turn red on;
        turn blue off;
    } else {
        turn red off;
        turn blue on;
    }
}

if you don’t want the loop to end, you can make it while(true). Configure your light sensor with the Motors and Sensors dialog (I can’t remember exactly where it is in the GUI off the top of my head, but it’s there), and you can read its value with the SensorValue() function.

Turning red and blue on and off depends on the interface with the light; if it’s the same as the standard NXT lamps, set the motor value corresponding to the port (eg. motor[motorA]) to 0 to turn it off, and to any other value up to 100 to turn it on at a given intensity (sign doesn’t matter; the intensity at 100 is the same as at -100).

3

The plan slightly changed, now it’s only one LED light. What i plan is when I press the button, the light will go on got weighted rings, and if I press the button and the button is unweighted, the light will not go on (maybe flash, not sure)

would this work?

task main()
{
while(true) {
if(sensorvalue[bucketlight] > 5) {
turn red on;
}
else
{
turn red off;
}
}

}

(i know a margin of > 5 is very small, but it’s the best i got)

4

“turn red on” and “turn red off” aren’t actual commands; you have to determine what the interface between the NXT and the LED is. If it’s the same as a lamp, you control it like this:

motor[motorA] = 100; // Turn port A lamp on
motor[motorA] = 0; // turn port A lamp off

Also, the code you have will respond to sensor changes, but will ignore controller input. To learn how to interact with game controllers, look at the FTC example programs provided with RobotC.