Add a pot to change timer of LED's, adjusting the pot resets the timer with out rewriting the sketch then loading it again and again to git just the right speed.
/*
For Loop Iteration
Demonstrates the use of a for() loop.
Lights multiple LEDs in sequence, then in reverse.
The circuit:
* LEDs from pins 0 through 12 to ground 5k pot at A0 adj timer
created 2006
by David A. Mellis
modified 5 Jul 2009
by Tom Igoe
modified Aug 2011 by Ayle
http://www.arduino.cc/en/Tutorial/ForLoop */
// Analog input pin that the potentiometer is attached to
int potpin = A0; // analog pin used to connect the potentiometer
int val; // variable to read the value from the analog pin
int timer; // The higher the number, the slower the timing.
void setup() {
// use a for loop to initialize each pin as an output:
for (int thisPin = 0; thisPin < 13; thisPin++) {
pinMode(thisPin, OUTPUT);
}
}
void loop() {
val = analogRead(potpin); // reads the value of the potentiometer (value between 0 and 1023)
timer = map(val, 0, 1023, 0, 254); // scale it to use it with the timer (value between 0 and 255)
// loop from the lowest pin to the highest:
for (int thisPin = 0; thisPin < 13; thisPin++) {
// turn the pin on:
digitalWrite(thisPin, HIGH);
delay(timer);
// turn the pin off:
digitalWrite(thisPin, LOW);
}
// loop from the highest pin to the lowest:
for (int thisPin = 12; thisPin >= 0; thisPin--) {
// turn the pin on:
digitalWrite(thisPin, HIGH);
delay(timer);
// turn the pin off:
digitalWrite(thisPin, LOW);
}
}
