Arduino - AnalogRead

Arduino

Guide

Tutorials

Reference

Hardware

Software

Forum

Playground

Exhibition

Hacking

FAQ

Buy

Language | Libraries | Comparison

## int analogRead(pin)

#### Description

Reads the value from a specified analog pin, the Arduino board makes a 10-bit analog to digital conversion. This means that it will map input voltages between 0 and 5 volts into integer values between 0 and 1024.

#### Parameters

You need to specify the number of the pin you want to read. It has to be one of the analog pins of the board, thus it should be a number between 0 and 5. It could also be a variable representing one value in that range.

#### Note

Analog pins unlike digital ones, do not need to be declared as INPUT nor OUTPUT

#### This function returns

An integer value in the range of 0 to 1024.

#### Example

    int ledPin = 13;   // LED connected to digital pin 13
    int analogPin = 3;   // potentiometer connected to analog pin 3
    int val = 0;   // variable to store the read value
    int threshold = 512;   // threshold

    void setup()
    {
      pinMode(ledPin, OUTPUT);   // sets the digital pin 13 as output
    }

    void loop()
    {
      val = analogRead(analogPin);   // read the input pin
      if (val >= threshold) {
        digitalWrite(ledPin, HIGH);   // sets the LED on
      } else {
        digitalWrite(ledPin, LOW);   // sets the LED off
      }
    }

Sets pin 13 to HIGH or LOW depending if the input at analog pin is higher than a certain threshold.

#### See also

- pinMode
- digitalWrite
- analogWrite

Reference Home Reference Home

Corrections, suggestions, and new documentation should be posted to the Forum.

Edit Page | Page History | Printable View | Recent Site Changes