The analog input is read and the result is printed in the Serial Monitor. When the shaft is turned all the way in one direction, there are 0 volts going to the pin, and the input value is 0. When the shaft is turned all the way in the opposite direction, there are 5 volts going to the pin and the input value is 1023. In between, analogRead() returns a number between 0 and 1023 that is proportional to the amount of voltage being applied to the pin.

This process is the foundational Analog-to-Digital Converter (ADC) mechanism intrinsic to the Arduino's core silicon. While digital pins are binary (ON or OFF), the physical world is analog. By routing a dynamic voltage through a physical Potentiometer (Variable Resistor), the Arduino captures exactly how much voltage is present and serializes that information to the Serial Monitor as a continuous 10-bit integer sequence.

Demystifying the 10-Bit ADC Array

When a raw voltage enters an analog pin like A0, the ATmega328P processor executes the ADC natively.

1. The 10-bit ADC quantizes the 0-5V range into 1024 discrete mathematical steps.
2. If the physical knob is at 0V (GND), it outputs 0.
3. If turned to 2.5V (half-way), the ADC returns 512.
4. If at the maximum 5.0V, the ADC returns 1023.

int sensorPin = A0;  // Explicitly defining the Analog-capable hardware pin!

void setup() {
  // Initiate the UART pipeline at 9600 Baud for Laptop communication
  Serial.begin(9600);
}

void loop() {
  // Execute the Analog-to-Digital reading cycle
  int sensorValue = analogRead(sensorPin);

  // Directly transmit the integer to the Serial Terminal
  Serial.println(sensorValue);

  delay(1); // 1 Millisecond stabilization buffer
}

Transforming Integers into Real Voltages

A raw serial number like "845" is not intuitive for measurement. To convert it back to a usable voltage, a simple mathematical transformation is applied:

• float voltage = sensorValue * (5.0 / 1023.0);
• This line multiplies the reading against the "Voltage per Step" ratio.
• The Serial Monitor will then display exact decimal voltages like 4.13V.

Required Hardware

• Arduino Uno/Nano (utilizing its 6 native Analog input pins A0-A5).
• Rotary Potentiometer (10K-Ohm) (functioning as a dynamic voltage divider).
• USB Data Cable (to sustain the continuous UART serial transmission stream).
• Arduino IDE Serial Monitor / Serial Plotter Tool (The Serial Plotter transforms the integer list into a smooth graphical wave, visually representing the analog rotation).