Libraries

To use a library in a sketch, select it from Sketch > Import Library. For details, see the page on the Arduino environment.

Standard Libraries

• EEPROM - reading and writing to permanent storage
• Ethernet - for connecting to the internet using the Arduino Ethernet Shield
• Firmata - for communicating with applications on the computer using a standard serial protocol.
• LiquidCrystal - for controlling liquid crystal displays (LCDs)
• Servo - for controlling servo motors
• SoftwareSerial - for serial communication on any digital pins
• Stepper - for controlling stepper motors
• Wire - Two Wire Interface (TWI/I2C) for sending and receiving data over a net of devices or sensors.

These libraries are compatible Wiring versions, and the links below point to the (excellent) Wiring documentation.

• Matrix - Basic LED Matrix display manipulation library
• Sprite - Basic image sprite manipulation library for use in animations with an LED matrix

Contributed Libraries

To install a contributed library, unzip it to the libraries sub-folder of your sketchbook. For details, see the page on the Arduino environment.

Communication (networking and protocols):

• Messenger - for processing text-based messages from the computer
• NewSoftSerial - an improved version of the SoftwareSerial library
• OneWire - control devices (from Dallas Semiconductor) that use the One Wire protocol.
• PS2Keyboard - read characters from a PS2 keyboard.
• Simple Message System - send messages between Arduino and the computer
• SSerial2Mobile - send text messages or emails using a cell phone (via AT commands over software serial)
• Webduino - extensible web server library (for use with the Arduino Ethernet Shield)
• X10 - Sending X10 signals over AC power lines
• XBee - for communicating with XBees in API mode
• SerialControl - Remote control other Arduinos over a serial connection

Sensing:

• Capacitive Sensing - turn two or more pins into capacitive sensors
• Debounce - for reading noisy digital inputs (e.g. from buttons)

Displays and LEDs:

• Improved LCD library fixes LCD initialization bugs in official Arduino LCD library
• GLCD - graphics routines for LCD based on the KS0108 or equivalent chipset.
• LedControl - for controlling LED matrices or seven-segment displays with a MAX7221 or MAX7219.
• LedControl - an alternative to the Matrix library for driving multiple LEDs with Maxim chips.
• LedDisplay - control of a HCMS-29xx scrolling LED display.

Frequency Generation and Audio:

• Tone - generate audio frequency square waves in the background on any microcontroller pin

Motors and PWM:

• TLC5940 - 16 channel 12 bit PWM controller.

Timing:

• DateTime - a library for keeping track of the current date and time in software.
• Metro - help you time actions at regular intervals
• MsTimer2 - uses the timer 2 interrupt to trigger an action every N milliseconds.

Utilities:

• TextString aka String - handle strings
• PString - a lightweight class for printing to buffers
• Streaming - a method to simplify print statements

For a guide to writing your own libraries, see this tutorial.

Reference Home

The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.