Arduino Interface ADC

What is ADC?

• ADC (Analog-to-Digital Converter) converts an analog signal (voltage) into a digital value.
• Arduino boards (like UNO, Nano, Mega) have an inbuilt 10-bit ADC.
  • 10-bit = 2¹⁰ = 0–1023 values.
  • Reference voltage = 5V (default on UNO).
  • So, each step ≈ 5V / 1024 ≈ 4.88 mV resolution.

Arduino ADC Pins

• On Arduino UNO, analog input pins are labeled as A0–A5.
• These can read voltage from 0 to 5V.

Real-world Use of ADC in Arduino

• Temperature sensors (LM35, TMP36).
• Light sensors (LDR).
• Gas sensors (MQ series).
• Sound sensors (microphone).
• Voltage monitoring in battery systems.

Circuit for Arduino Interface ADC

Arduino Interface ADC Schematic

Read ADC Value and print in (UART) Serial

 

Code

//www.aruneworld.com

int potPin = 0;
 
void setup() 
{
  Serial.begin(9600);
}
 
void loop() 
{
  int reading  = analogRead(potPin);
  Serial.println(reading);
  delay(500);
}

 

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 Line by Line Explanation

1. int potPin = 0;
   • potPin is assigned to analog pin A0.
   • In Arduino, 0 means A0, 1 means A1, and so on.
2. void setup()
   • Runs once when Arduino starts.
   • Serial.begin(9600); initializes Serial Communication with the PC at 9600 bits per second.
   • Needed to print data on Serial Monitor.
3. void loop()
   • Repeats forever.
   • int reading = analogRead(potPin);
     • Reads the analog voltage (0–5V) at pin A0.
     • Converts it to a 10-bit digital value between 0 and 1023.
       • 0 → 0V
       • 512 → ~2.5V
       • 1023 → ~5V
   • Serial.println(reading);
     • Prints the numeric value to the Serial Monitor on your PC.
   • delay(500);
     • Waits 500 ms before the next reading.
     • So you see 2 readings per second.

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Circuit Setup

• Use a potentiometer (10kΩ):
  • One side → 5V
  • Other side → GND
  • Middle pin → A0 (analog input)

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Example Output (Serial Monitor)

If you rotate the potentiometer:

0
120
350
700
1023

(Values change based on position of knob).