const int analogPin = A0; // Pin connected to the potentiometer 
const int ledCount = 9; // Number of LEDs
int ledPins[] = {2,3,4,5,6,7,8,9,10}; // Pins connected to the LEDs 
void setup() {
 for (int thisLed = 0; thisLed < ledCount; thisLed++) {
 pinMode(ledPins[thisLed], OUTPUT); // Set the LED pins as output
 }
}
// Start a loop
void loop() { 
 int sensorReading = analogRead(analogPin); // Analog input
 int ledLevel = map(sensorReading, 0, 1023, 0, ledCount);
 for (int thisLed = 0; thisLed < ledCount; thisLed++) {
 if (thisLed < ledLevel) { // Turn on LEDs in sequence
 digitalWrite(ledPins[thisLed], HIGH);
 }
 else { // Turn off LEDs in sequence
 digitalWrite(ledPins[thisLed], LOW); 
 }
 }
}