LED bargraph (pot level meter)

A VU-meter on the bench: the ATmega328P reads the trim pot with its real 10-bit ADC and lights a six-LED bar on D8-D13, green through red, one LED per ~160 counts. Click the pot and drag its Position slider in the Inspector to sweep the bar up and down; the raw reading prints over serial. The Code tab holds the same meter as an editable Arduino sketch.

What's on the bench

• 6× LED
• 6× Resistor
• Arduino Uno
• Battery
• Trim Pot

The code

This Arduino C++ sketch lives in the Code tab; sign in and press Compile & upload to build real firmware for the emulated board.

// The same level meter as an Arduino sketch. Edit it, then Compile &
// upload (sign-in needed): the server builds real AVR firmware.
const int POT = A0;
const int LEDS[6] = {8, 9, 10, 11, 12, 13};  // green -> red

void setup() {
  for (int i = 0; i < 6; i++) pinMode(LEDS[i], OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int v = analogRead(POT);        // 0..1023 from the real ADC
  int level = min(6, v / 160);    // one LED per ~160 counts
  for (int i = 0; i < 6; i++) digitalWrite(LEDS[i], i < level);
  Serial.print("A0 ");
  Serial.println(v);
  delay(200);
}