# Newbie Question

I am creating an LED bouncing ball effect with 10 LED’s set up as an array, bouncing from 9 - 0 - 8 - 0 … and want to use a simple method of coding the last highest LED (-1) as the maximum ‘bounce point’ and then returning to 0 and so on. I am unsure of how to most effectively use the minus sign.

I did have success using the following code to get the LED to bounce from LED 10 back to 0 and then to 9:

``````void changeLED() {
// turn off all LED's
for (int x=0; x<10; x++) {
digitalWrite(ledPin[x], LOW);
}
// turn on the current LED
digitalWrite(ledPin[currentLED], HIGH);

// increment by the direction value
currentLED += direction;
if (currentLED == 0) {direction = 1;}
if (currentLED == currentLED1) {direction = -1;}
``````

with int currentLED = 9
int currentLED1 = 8

However, trying to use this principle any futher does not seem to work.

Any help would be appreciated.

well, if the limits are 0 and currentLED1 ("maxLED" might be less confusing), then let currentLED start somewhere between those extremes or you might "bounce" outside the allowed range.

Thanks for that, makes sense.

I will give it a shot and report back.