:: Interfacing with Hardware ::

These topics cover the hardware and software setup required to connect an Arduino device with a variety of electronic parts, chips and devices. A related topic not covered under this section is the shield, boards that plug directly into an Arduino's pin layout. Information on the creation and use of specific shields belongs in that section. Information on shields in general and their creation belongs here.

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Navigation

Output

• Visual
  • LED Lights and Displays
  • LCDs
  • Video
• Audio
  • µC Hobby Arduino Sound Tutorial
  • Realtime audio processing
  • Tone Generation Libraries
  • Synthesizers and sound generation
  • MIDI
• Physical/Mechanical
• Multiplexing

Input

• Visual/IR
• Audio
• Mechanical
  • Switches and Buttons
  • Encoders
  • Potentiometers

Storage

Communication

• Serial
• Ethernet
• WiFi

General

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Output

Examples and information for specific output devices and peripherals: How to connect and wire up devices and code to drive them.

Visual

• Camera Control - Controlling Cameras
  • Remote control a Canon EOS to take time lapse photos. The same wiring and interface should work on other cameras.
  • Infrared controlled timelapse photography with Canon DSLRs. Works with all cameras that are compatible with the Canon RC-1 remote.
  • Imitating a Nikon IR Remote for Nikon SLR's.
  • Remote control a Nikon camera via infrared LED
  • AI-1 ("All-in-one") Remote - A Photographic Accessory That You Can Build. A fully featured intervalometer by Tom Lackamp. Does a lot, but is also quite a big/complex project.
  • A device to trigger camera and flash forum discussion (english) pointing to this page (not english).
  • Controlling camera shutter, flash and more via 3 pin plug. Forum discussion with sample code. Should be quite generic, tested with Canons and Olympus SP510UZ.
  • IR remote for canon digital camera. Unresolved forum discussion. Sample code and pointers of how to get it working.
  • Canon RC-1 compatible IR remote. All you need is one IR LED and an Arduino board.
  • Links to the Sony LANC protocol. This can be used to control video cameras, and a subset of it might be used to control still cameras (Arduino-LANC Code).
  • LANC Arduino full application + circuit Another approach to implement LANC control with Arduino, including open collector circuit you need to interface with the camera.
  • High Speed Photography: using an Arduino connected to a microphone and camera flash to capture images of peeps exploding.
  • Triggering a Camera’s Flash with Sound and Light - complete with photos and hand-drawn schematics.
  • Intervaluino: An Arduino-powered intervalometer for taking time-lapse photo sequences.
  • DIY camera motion control: An Arduino-controlled stepping motor and an IGUS DryLin W rail allow smooth camera moves.
  • OpenMoco: A complete time-lapse motion control system, integrating intervalometer, multiple motor axes, action scripting, and keyframing in a single arduino.

• LED Lights and Displays
  • lightuino: Arduino 328 software and shield compatible board drives 70 LEDs through 70 individual channels (i.e. constant drive, not matrix strobing) using the M5451 constant current chip. FOSS source code available at http://code.google.com/p/arduino-m5451-current-driver/. Also contains instruction on how to wire up the M5451 chip to Arduino yourself. Buy
  • Controlling an Alphanumeric LED Display - Library on Blogspot
  • Controlling a Led matrix with the MAX7219 and MAX7221. An extensive collection of articles, schematics and software libraries.
  • Schematic for driving multiple leds from one Arduino pin.
  • hc4led - A cheap 4-digit seven segment LED display with SPI. No decimals, though. Sample code here: Hc4led. And here's an easy-to-use Arduino/Wiring library for controlling these displays. The Reaction Time Tester project uses the HC4LED library.
  • Twitter LED Scroller - Twitter API to PHP to Processing to Arduino to 74HC595 to scrolling LED matrix (complete with cool resin case).
  • POV - Arduino does persistence of vision, too.
  • 8 x 8 LED grid
  • Matrix LED backpack - Code for running the Sparkfun RGB matrix LED backpack.
  • RGB monome clone - controlling an RGB led / button matrix.
  • THE Octinct - Arduino based RGB Monome 64 clone.
  • bonome - Arduino based RGB Monome 64 clone with sparkfun button pads
  • 4 by 4 RGB monome clone - controlling an RGB led / button matrix using the TLC5940.
  • Direct driving of an 8x8 LED matrix with no ICs or other components involved.
  • Arduino mood light with a 3W RGB LED.
  • 3x3 LED Cube Diecimila Shield
  • ShiftBrite - A 10 bit RGB LED module.
  • Knight Rider extensions - an extension to the learning loops example.
  • TLC5940 - constant-current LED driver with 16 channels of 12 bit PWM output. Chips can be daisy-chained for >16 PWM channels. Library code and examples available.
  • 8x8 RGB PWM Matrix The driver includes an ATmega168 and can be programmed via ICSP or the bootloader + USB/TTL cable. It is code compatible with Halley's shield.
  • LED: simple hardware abstraction library
  • Rainbowduino: An Arduino-compatible board that can drive an 8x8 RGB matrix, or 192 discrete LEDs.
  • RGB LED Color Mixing using 10k potentiometers : Simple tutorial on getting color mixing with 10k pots.

• LCDs
  • have their own page

• Lighting Control
  • DMX lighting control

• OLED
  • Some code samples to control output to a small surface-mount OLED with basic hardware-level graphics functions

• Video Output
  • MicroVGA Library for MicroVGA-TEXT devices, allowing Arduino to display on a VGA (LCD/CRT) monitor or a television and read keystrokes from a PS/2 keyboard.
  • SID-emulator The shield contains an emulator of the audio chip in a Commodore 64. The systems allows you to create original 8-bit video and sounds programmed and controlled via the Arduino board.
  • Bitmap picture display on a graphics shield
  • Picaso Library for interfacing with 4D Picaso devices (including the 4D uVGA Picaso MD1)

• IR Remote Output
  • IR remote library to control Sony, NEC, RC5, and RC6 devices.

Audio

• µC Hobby Arduino Sound Tutorial
  • Part 1: various strategies to generating sound.
  • Part 2: "hello world", simple tone generation.
  • Part 3: playing a melody.

• Tone Generation Libraries
  • Arduino Tone Library: A library that can be used to generate tones in the background using timers while your Arduino does other things.

• Realtime audio processing
  • realtime audio: digitizing sound and audio effects.

• Synthesizers and sound generation
  • Freqout function in the code library
  • Arduino Synth - general page for Arduino synthesizer work
  • see dusjagr labs for an easy way to control a resistor in a circuitbent toy or a simple analog electronic circuit for lo-fi music (driving a photoresistor with a LED output from the Arduino)
  • Arduino Polyphony
  • handmade Arduino Auduino shield
  • Smapler v2 shield for stereo sound generation homework help
  • arduinOSC library for arbitrary waveform generation
  • Summer simple hardware abstraction library that can playFrequencies and beep
  • Arduino DDS Sinewave Generator

• MIDI
  • see MIDI under communication section

• Audio Device and Module Control
  • Control an iPod with the Arduino, by Jonas Olson & Robert White.
  • Connect Arduino to the YAMPP III Industrial MP3 player, diagrams by Jens Wunderling.
  • Some code for controlling an Ipod remote through Processing, by Rosie Daniel.
  • VMUSIC Mp3 Module
  • Record and play audio with ISD1700 chipcorders
  • Mediaplayer for Adafruit's Waveshield

• SID
  • SID-emulator The shield contains an emulator of the graphics/audio chip in a Commodore 64. The systems allows you to create original 8-bit sounds programmed and controlled via the Arduino board.
  • Vintage Gameboy and SNES -like sound using Yamaha chips (YM294, YM2149)

• Gakken SX-150
  • MIDI-to-Gakken using Arduino

Physical/Mechanical

• Motor Control
  • Eagle files for an L293-based Arduino motor driver shield.
  • Code the parallax HB-25 motor controller item code #29144.
  • DC motor control using an H bridge.
  • Adafruit servo/stepper/motor shield - controlling 2 servos, & up to 2 stepper motors or 4 DC motors. (Schematics, layout, and library).
  • Datasheet for the L293 motor driver IC. Blog diagram of how to connect the L293 to an Arduino. (Peltier Elements are working with this IC, too)
  • TankShield - a tank tread shield for the Arduino that shows how to turn an arduino into a robot
  • DC Motor Control - Speed and Direction
  • DC motor control using L293D (with and without PWM).
  • directional motor control with a L293D
  • PC Fan Speed Control - Reading RPM
  • Library for Pololu Qik2s9v1 controller
  • Controlling OSMC Boards with an Arduino

• Bipolar Stepper Motor from Floppy Drives
  • Using the stepper motors from old Floppy Drives PL15S-020 bipolar stepper motors Code Link, using no external chips.

• Solenoids
  • Schematic for driving DC solenoids, using a transistor connected to an Arduino pin.
  • A Solenoid Tutorial.

• Servos
  • Mega Servo
    • Control up to 12 servos with the MegaServo library.

  • Software Servo
    • You can control up to 20 hobby servos simultaneously with the Software Servo Library.
      • Example controlling a servo with the Software Servo Library.
      • Example xylophone with wine glasses built with the Software Servo Library.

  • Hardware timer Servo
    • You can control 2 servos, on pin 9 and 10, very precisely with the Servo Timer 1 Library.
    • You can control 2 servos, on pin 9 and 10, with even more precision with the ServoTimeTimer1 Library based on the above.
    • You can control very large numbers of servos precisely using an external PWM chip. Each chip can control up to 16 servos and can be daisy-chained for > 16 outputs. See PWM Expansion with TLC5940 for library code and examples.
    • Code and instructions for using the Atmega's internal hardware timers to drive two servos.
    • Control up to 12 servos on a standard Arduino or 48 servos using the Mega Board with the MegaServo Library
  • Arduino and Pololu Micro Serial 8 Servo Controller. Video, images and sketch files to manage 6 servos from a joystick
  • Controlling up to 8 servos with Pololu Micro Serial Servo Controller. Forum discussion with sample code.
  • Manage two servos using a joystick and create multiple movements with the Lynx Tilt Kit

• Robot Kits
  • Put Arduino in the Asuro Robot's brain.
  • Asurino - an Arduino library for the Asuro robot.
  • Arduino takes over RoboSapien V1 with 4 wires.

• Other
  • Control a clock movement.
  • Model Railroad Fast Clock, using an Arduino to drive analog clock hands at selectable speeds. Includes sketch.

Electrical / High Power

• Relays
  • Schematic for driving DC relays using a transistor connected to an Arduino pin.
  • Schematic for driving 5V DC relays using an optical coupler and a transistor connected to an Arduino pin, which is protected by the optical coupler. Based on the schematic above.
• Voltage Boosters
  • A simple regulated DC-DC booster for up to 60V 1/4W. It uses no special ICs, just basic components and two pins from the Arduino.

Multiplexing

• How to use TLC5940s to add more PWM outputs.
• 4051 is an 8 channel analog multiplexer / demultiplexer
• PWM
  • PWM all Arduino pins without extra hardware
  • [http://effluviaofascatteredmind.blogspot.com/2010/02/arduino-pwm-on-all-pins.html|A class (i.e. library) to PWM all pins between any 2 states]
• M5451 Constant current output pin expander
  • Connecting M5451 to Arduino
  • Source code
  • Prebuilt hardware

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Input

Examples and information on specific input devices and peripherals: How to connect and wire up devices and code to get data from them.

Visual/IR

• Light Sensors
  • Example of how to use an LED as a light sensor.
  • Example of how to use several LEDs as a light sensor and display the results with Processing.
  • Example of how to Build a simple tachometer using an optoswitch based circuit.
  • Example of how to use an IR LED and sensor to detect a broken beam. With a simple game of Sneak_Thief.
  • Tutorial on interfacing the TSL230R light sensor and the Arduino
  • Library for directly connecting your Arduino to the Pixart sensor taken from the Wiimote handset. PVision library for Pixart/Wiimote IR sensor Can be used for X/Y blob tracking (at 100Hz) of up to 4 points. Note: you will need to build a harness circuit for the Pixart sensor.
• IR Reflectance/Line Sensors
  • Library for connecting your Arduino or Orangutan to Pololu QTR reflectance sensors, which can be used for line following, edge detection, or close-proximity obstacle detection/ranging.
• Video
  • read analogue video (PAL or NTSC)

Audio

• Microphones
  • Example of how to connect a piezo as a blow sensor, can also be used to read vibrations or as a touch sensor.
  • Example of how to connect a electret microphone.
• MIDI
  • see MIDI under communication section

Mechanical

• Switches and Buttons
  • Debounce: a library to debounce switches.
  • SoftwareDebounce: a simple software input debounce algorithm.
  • Buttons: a simple library to use hardware debounced buttons, handling one shot and hold.
  • HoldButton: a code that makes a single button able to call different functions depending upon how long it it is held.
  • Button: simple hardware abstraction library
  • AnalogButtons: a library to connect more than 1 switch to a single Analgue pin, using different voltage dividing resisters for each switch. Provides register callback functions or over-riding Button class methods to communicate a button press action. Supports configurable holding down of a Button.
  • AdvButton: Advanced, yet simple to use, library for registering user input with buttons. Provides an event based interface.

• Encoders
  • A little sketch for reading rotary encoders.

• Potentiometers
  • Potentiometer: simple hardware abstraction library

Input Devices

• Joysticks / Gamepads
  • A good tutorial on how to connect five or more joysticks to the Arduino
  • NESpad library that handles the serial communication between Nintendo NES/SNES game pads and an Arduino (moved from rahji.com) http://code.google.com/p/nespad/
  • Talking to a Wii Nunchuck. Adapter and Library at Todbot http://todbot.com/blog/2008/02/18/wiichuck-wii-nunchuck-adapter-available/
  • Talking to a Wii Classic Controller
  • Another Wii Nunchuck library with more accurate angular pitch and roll data WiiChuckClass.
  • A library to read a standard Playstation controller PSX Library.
  • A library to read a standard, wireless, or dualshock Playstation controller in digital or analog mode as well as control feedbackAnalogPSXLibrary
  • Converting Wii gamepad signals to USB HID, compatible with PS3 and Windows : http://code.google.com/p/wii-ext-to-usb/.
  • Interfacing Wii Guitar Hero World Tour Drum controller. Interface described at: http://jamers.netne.net.
  • Wii NunChuck, Arduino and servos (video, images and source code) http://www.fabiobiondi.com/blog/2009/12/wii-nunchuck-controller-and-arduino/.
  • Wiimote and PS3 controller on arduino using USB-Host shield: http://www.circuitsathome.com/mcu/programming/ps3-and-wiimote-game-controllers-on-the-arduino-host-shield-part-1
  • Using a standard PC joystick or gamepad directly: http://www.built-to-spec.com/blog/2009/09/10/using-a-pc-joystick-with-the-arduino/

• Mouse
  • Read data from a PS2 mouse. Useful if you want to use the encoders from an old mouse in a robot or other device. PS2 mouse interface
  • PS2 Mouse Library - An updated version of the above library that adds support for scroll wheel mice and easier sketch integration.
  • Read out the surface movements directly from an optical mouse sensor. English tutorial and library
• Keyboard/Keypads
  • Keypad - Read a keypad with up to 16 keys. See Keypad Tutorial.
  • PS2Keyboard - A small library that deals with PS/2 based keyboards
  • PS2KeyboardExt - An extension to the above library to support more keys and functions
  • PS2KeyboardExt2 - another extension, fast with shift, alt and caps lock and caps_lock light
  • I2C Port expander and Keypads - A small library for use keypads with I2C port expander PCF8574
  • I2C Port expander and Decoders - A library that uses a 74C922 keypad decoder on an I2C port expander

Capacitive Sensing

• Up to 6 capacitive sensors (touch) without additional hardware
• Arduino as capacitive sensor
• Theremin as a capacitive sensing device
• QTouch 1-wire Library - Library for the 1 wire interface on Atmel QTouch devices (developed for QT1103)

Pressure Sensing

• SCP1000: Code to read the SCP1000 barometric pressure/temperature sensor, which uses the SPI interface.

Ardustat: Galvanostat/Potentiostat

• Ardustat: Schematics and code to build an electrochemical characterization devices using an Arduino.

Distance Sensing

• http://www.arduino.cc/en/Tutorial/UltrasoundSensor - I just wanted to point out that this code also works for the Maxbotix Max Sonar ultrasonic range finder... which is sold in the USA through SparkFun Electronics...

• MaxBotix/MaxSonar tutorial: I have found the above PING code doesn't work with MaxSonar devices so I did a small writeup.

• Parallax Ping - code http://www.arduino.cc/playground/Main/UltrasonicSensor - Variant of the code above but returns actual distance.

• GP2D12 infrared sensor - read_gp2d12_range is a function that retrieves distance from this sensor in centimeters.

• Simple IR distance sensor using a Panasonic IR sensor and IR led using the IR sensor and led from the boe bot kit. http://www.arduino.cc/playground/Main/PanasonicIrSensor

• URM37 Ultrasonic Distance Measurement Library.

- URM37 Ultrasonic Distance Measurement Library by Miles Burton

• SRF08 Ultra Sonic Range Finder Code - http://www.arduino.cc/playground/Main/Sonar_srf08 Communicate with old SRF08 sensor via Wire.h protocol. Choose inch or centimeters and change address.

Slot Detectors

• schematic for connecting a "slot detector" to Arduino Δ

Environmental

• Temperature
  • KTY 81-* KTY (NTC) Tempertaure sensor with Arduino
  • Dallas Temperature Control Library. A very simple library to interface with the DS18B20, DS18S20 or DS1820 IC.
  • A simple lookup table method of getting Celcius numbers from a 10k thermistor. Code & calculating spreadsheet here: thermistor
  • Reading a thermistor using an equation instead of a lookup table. thermistor2
  • Single line of code to read thermistor from 1C to 44C: thermistor3
  • There are also ways to access the excellent Dallas 1-Wire temperature sensors.OneWire
  • Extremely easy-to-use Arduino library for the Sensirion SHT1x temperature and humidity sensor, which also calculates the dew point (sensor available at nuelectronics).
  • Simple Library to interface a Maxim MAX6675 Thermocouple to Digital Temp Converter. (Google Code
  • Reading from SMT16030 digital temperature sensors
  • LM75A i2c temperature library
  • Microchip MCP9700A Temperature Sensor Library -40C to +125C for $0.36US!
• See also Visual / Light Sensor
• See also Dallas One-Wire Interface

Tagging / Labeling

• RFID
  • GumboLabs write-up on how to get the best out of your Parallax RFID reader and how to account for noise. Using the Parallax reader and accounting for noise.
  • Code for using the Parallax RFID? reader with Arudino. Based on the Wiring tutorial.
  • Code for using the Parallax RFID reader with Arudino. Based on the Wiring tutorial.
  • Innovations ID-12 RFID Reader (from sparkfun)
  • Innovations ID-12 RFID Reader using software serial and detecting removed RFID tags
• Barcode
  • You can hook up a bar code scanner (which simulates a keyboard) or a keyboard to the arduino. See bar code scanner

Location

• Compass
  • HMC6352 I2C Compass Sensor - Read heading from a compass sensor, using the Wire library. Here's the sketch: Learning.hmc6352
  • Forum posting on controlling the HMC6352 with the Wire library.
  • Parallax HM55B Compass Sensor - get angle to North here is all you need: HM55B

• GPS
  • Arduino code for parsing data from the EM-406 GPS module, by bigengineer.
  • How to connect a Parallax GPS module to the Arduino, and read its $GPRMC string. Tutorial translated from Igor González Martín's original Spanish tutorial. This allows you to get date, heading, latitude and longitude from the GPS module.
  • GPS library for Arduino/Wiring by Maarten Lamers is a library for decoding (NMEA) data from any GPS receiver. It extracts all information types, such as speed, direction, location. Supports $GPRMC and all possible sentence types. Includes example programs and routines for calculating distances and directions over Earth's surface. NOTE: this library does not work on 1K Arduinos: Duemilanova, etc.
  • TinyGPS, a new GPS/NMEA parser by Mikal Hart is a resource stingy library for decoding (NMEA) data from any GPS receiver. It extracts speed, direction, location, course, date, and time, but consumes only about 100 bytes of RAM.
  • Acoustic.GPS A GPS homebrew "GPS" system that uses sound to determine distance to three known points using off the shelf components.

Motion

• Accelerometers
  • Connect the Arduino to the LIS3LV02DQ Triple Axis Accelerometer
  • Connect and read the Parallax 2-axis Memsic 2125 accelerometer - instructions, video, and source code
  • Connect Arduino to a Parallax H48C 3-axis accelerometer H48C Triple Axis Accelerometer (DE/EN) Parallax H48C
  • Interface to the Parallax visual motion sensor - some instructions and code samples
• Compass
  • Using CMPS03 compass module on Arduino connected through I2C - Manuals

Electrical / High Power

• DC
  • Arduino can only sense 0-5V inputs. Here's a schematic explanation of how to interface to 5V or higher.

• 120v AC

Time

• Time library for dates and times that can be used with and without external hardware
• A tutorial for a DCF77-based radio clock
  • Tutorial Arduino DCF77 v0.2 Code
• Use the Dallas/Maxim DS1306 Real-time Clock chip with Arduino.
• I2C for RTC DS1307 Real Time Clock - Interfacing with the DS1307 date/time keeping clock - Great for logging events.
• Library to control the RTC DS1307 with Arduino. Also an example is supplied and how to connect it. RTC DS1307 Library
• Use the CMax CMMR-6P WWVB Receiver with Arduino
• DS1302 RTC (spi based with supercap backup) library
• Sleep and Watchdog functions for battery operated equipment Nightingale example
• Interface to IBM AT RTC bq3287 and compatable with 8bit bi-directional bus code and description

Touch screen

• Schematics and source code available for interfacing to a small touchscreen (mounted on the TouchShield) - and another example
• Schema + sources to plug DS Touchscreen with an Arduino (from A to Z)

Multiplexing

• read the forum post on analog multiplexers
• learn how to use the Motorola MC14067BCP Analog multiplexer/demultiplexer through the fluidforms tutorial
• The 74XX151 digital multiplexer
• 4051 is an 8 channel analog multiplexer / demultiplexer
• Want to learn how to make your own force-sensors and how to connect hundreds of them with multiplexers? look at fluidforms' great tutorial and post in the Arduino users projects section of this wiki. Tutorial by fluidforms.at.
• Build a 24/48/72 Channel Input Extender

Shift Registers

• The SN74HC165N 8-bit parallel-in/serial-out shift register. Read the state of 16 (or more) digital pins using only 4 Arduino digital pins.

ADC/DAC

• Need more, or more accurate, analogue input and output? Use an ADC or DAC.
• The MCP3208 is a 12bit 8 channel SPI ADC.
• The R/2R ladder is a simple and inexpensive alternative to DAC ICs - photo-tutorial for construction on a protoshield.
• Connect a LTC2400 High Precision 24 Bit Analog to Digital Converter
• Tutorial on rolling your own voltage dividers as a PDF document (with optional data files)
• Using a AD420 Serial Input 16 bit DAC with Arduino
• Connect a MCP4725, I2C-based ADC with Arduino.
• Arduino library for the Texas Instruments ADS7828 12-bit, 8-channel I2C A/D converter (i2c-adc-ads7828)

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Storage

Various options for storing data from your Arduino board.

Built-In EEPROM

• The EEPROM library give you access to 512 bytes of non-volatile memory (that is, it retains its value when you turn the board off).

Built-In Flash

• Mikal Hart's Flash library allows you to easily store strings, arrays, and tables in read-only memory without the hassle and complexity of learning PROGMEM programming.

USB Memory Stick

• Datalogging to a USB memory stick with ftdi board usb memory nick?

DataFlash Memory

• Dataflash memory library

I2C EEPROM

• Interfacing an I2C EEPROM
• 24LC512 I2C EEPROM Driver
• 24C1024 I2C EEPROM Library

SD / MMC Card

• Interfacing SD / MMC Card with SPI
• Using the EthernetShieds SD Slot with HardwareSPI
• sdfatlib Library to Interface with SD-Cards

Spi RAM

• Library to interface with a 23K256 Spi SRAM chip

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Communication

Information on communication protocols often used to talk with other devices. Please refer to Interfacing with Software for information on linking with various PC based applications. This listing may contain cross-listings with device type listings above.

Serial

• Simple Soft Serial, No library http://www.arduino.cc/en/Tutorial/SoftwareSerial
• SimpleTX configuration USART SimpleTX
• See also InterfacingWithSoftware - Specifically interfacing Arduino as a Linux TTY
• NewSoftSerial - Mikal Hart's replacement for SoftwareSerial -- derived from ladyada's AFSoftSerial.
• Communication through files - A really quick and easy way to communicate with any software of your choice.
• Messenger: Send, receive and parse characters, integers and lists. It is the new SimpleMessageSystem.
• CmdMessenger: A small extension of Messenger above.
• SimpleMessageSystem: Send, receive and parse characters, integers and lists between Arduino and Max/Msp or Pure Data
• General purpose program to control most Arduino functions via serial communication with a computer- reads state on dig & analog input pins and sends data to the output pins
• How to pass large multi-byte values between two Arduinos, or shields. If Serial.Print doesn't do the job, try these functions to bit shift multiple bytes together to reconstruct integers or floats
• A standalone printFloat function with no library imports
• Modbus RTU Master/Slave implementation of the functions read holding registers and preset multiple registers (function codes 3 and 16 respectively).
• ModbusMaster: This is an Arduino library for communicating with Modbus slaves over RS232/485 (via RTU protocol). Discrete functions 0x01 - Read Coils, 0x02 - Read Discrete Inputs, 0x05 - Write Single Coil, 0x0F - Write Multiple Coils and register functions 0x03 - Read Holding Registers, 0x04 - Read Input Registers, 0x06 - Write Single Register, 0x10 - Write Multiple Registers, 0x16 - Mask Write Register, and 0x17 - Read Write Multiple Registers implemented. Project is hosted at Google Code.
• The MuxShield collects serial output from up to 5 slaves vis software and sends it out to the serial hardware port.
• SerialControl remotely controls Arduinos (usable in a XBee peer2peer network!)
• iPodSerial Library to interact with iPods over serial through their dock connector. Supports Simple Remote and Advanced Remote modes.

SPI

• Spi library for Serial Peripheral Interface.

PWM

• Modifying the PWM frequency

uM-FPU V3.1 Floating Point Coprocessor

• Fpu library for using the uM-FPU V3.1 Floating Point Coprocessor.

2B

• 2B is a simple protocol used to receive and send messages to Arduino

PS2

• PS2 mouse interface

Phones

• Symbian 60 Phones

HDMI-CEC

• HDMI CEC Library communication with HDMI CEC capable devices (TV, DVD, Receivers, BR) : power on/power off/input selector.

Ethernet

• GumboLabs write-up on how to get the best out of the Ethernet shiled. Also explains connecting to a Rails app. Arduino Ethernet Shield and Rails.

• The "official" Arduino Ethernet Shield uses the w5100 chip from WizNet.

• Arduino Ethernet Library by gkaindl enabling DHCP, DNS and Bonjour on Arduino

• Here is a blog describing how to connect to an internet chat server using the Arduino and a Lantronix ethernet module.

• Nuelectronics has developed an Ethernet shield for the Arduino with schematic, open-source ethershield library and webserver demo using Microchip's ENC28J60 SPI ethernet controller. The open-source TCP/IP stack is in arduino library format, easy to use and available for downloading.

• Adafruit XPort/Ethernet shield - How to connect a Lantronix XPort to an Arduino, includes schematic & library. Examples of reading POP email, webserver, sending & receiving twitters...

• a Web Server example, made using an Ethernet Shield.

• the Webduino library, a modular web server for the Arduino Ethernet Shield and AdaFruit shield using the Wiznet module that can be integrated into your sketches. It comes with several examples.

• RADIUS Client, Classes for creating, sending and receiving RADIUS requests as per RFC 2187 and 2188. For ArduinoMega and Ethernet shield.

• MQTT Client, provides a client for doing simple publish/subscribe messaging with a server that supports MQTT v3. For the Arduino Ethernet Shield. For more information about MQTT, visit http://mqtt.org.

WiFi

• AsyncLabs has a WiFi shield for the Arduino using ZeroG Wireless's ZG2100 WiFi device. It comes with a WiShield library which includes the driver source code, a TCP/IP stack and a bunch of sample sketches demonstrating the use of the Arduino as a web server and a web client. More information about using the sketches can be found on the AsyncLabs wiki page.

Flash / Flex

• Arduino and Flash: modify your existent Flash games to work with a joystick
• Arduino and Flex: connect a joystick to your application

DMX

I2C / TWI

• Learning I2C / TWI (Two-Wire Interface)
• Arduino I2C Expansion I/O: detailed tutorial on getting I2C working.
• Arduino and the Two-Wire Interface (TWI/I2C) interfacing with a LIS3LV02DQ accelerometer.
• I2C for X9241 Digital Potentiometer - Interfacing with the X9241 Digital Potentiometer
• I2C for RTC DS1307 Real Time Clock - Interfacing with the DS1307 date/time keeping clock - Great for logging events.
• Using i2c Based LCD displays, including library and suggested API

Dallas One-Wire Interface

• OneWire Interface: Tutorial on one-wire interface and DS1820 series temperature probes
• DS2482 library: Library for using Maxim DS2482-100/800 to interface with one-wire devices

MIDI

MIDI Library

MIDI-out (sending midi data to another device)

• Ardrumo: software to convert serial data coming from the Arduino into Mac OS X MIDI drum data (i.e. how to get Arduino talking to GarageBand without buying any extra hardware).
• S2MIDI - Windows (.NET) program for converting serial data from Arduino into MIDI messages (hosted on Google Code)
• ttymidi - a GPL-licensed program that allows an Arduino board to interface with Linux ALSA MIDI applications without any additional hardware.
• Make your Arduino into a MIDI drum controller with Todobot's tutorial
• The Midi Out tutorial from the fine folks at ITP.
• A blog on building a midi guitar pick using the Arduino.
• read six sensors and send their values as Midi CC messages
• Effects Processor Controller via MIDI
• MIDI Touchpad hardware and software using PS2 Touchpad as a MIDI Device. Real MIDI, not translated by Desktop app.
• 16 MIDI Drums 10 switched and 6 velocity sensitive drums
• MIDI Projects
• Wii Guitar Hero World Tour Drums MIDI Out interface at http://jamers.netne.net.

MIDI-in (receiving and interpreting midi data with an Arduino)

• Forum link, basic code and setup. Control LEDs with a midi keyboard.
• MIDI Analyser Simple MIDI Analyser, using LED's to display MIDI status.
• MIDI Glockenspiel Toy Glockenspiel MIDI driven, using solenoids.

Wireless

• Bluetooth
  • Wireless communication with PC and Arduino board using bluetooth, by Mitchell Page.
  • http://www.mitchellpage.com.au/research/?p=263
• Wireless communication with Cell phone and Arduino board using bluetooth, by Bakalski Page http://www.microcontroller-bg.com/btterm This is a bluetooth cell phone terminal software (like HyperTerminal but for Cell phones)
• A Tutorial on setting up Arduino BT on Mac OS X Tiger
• How to set up the BT ON Windows XP with an external BT adapter.
• If you have the rare need to reprogram your BlueGiga module, here's a tutorial on how to build adapter.
  • See also

• ZigBee / XBee
  • The XBee Shield by M. Yarza, the Arduino Developer at Libelium
  • Schematics and Eagle files for M. Yarza/Libelium's Xbee shield
  • Arduino and Xbee(ZigBee), Interface Circuit (AXIC), by Thomas Ouellet Fredericks (tof).
  • Step by step tutorial for setting up 2 Xbee shields from scratch with code samples
  • Xbee Programming Arduino Wirelessly, by Tom Igoe.
  • Arduino to Xbee, from Beatriz Da Costa's course outline.
  • MaxStream's XBee ZigBee RF Module
    • Product manual (802.14.4) PDF, 69 pages.
    • Product Manual (ZigBee) PDF, 46 pages.
  • xbee-arduino: an Arduino library for communicating with XBees in API (packet) mode. Supports I/O samples, TX/RX, AT Command, and Remote AT for both series 1 and 2 XBee radios

• Nordic Nrf2401
  • A wireless communication library for using the small, fast and bi-directional Nordic's Nrf2401 radio transceiver.

• Nordic Nrf24L01
  • A simple library for the nRF24L01(+).

• PCR-1000
  • A icom PCR-1000 controlled by a Arduino- here

• EasyRadio
  • Connect Arduino to the EasyRadio transceiver module, diagrams by Jens Wunderling.

• VirtualWire
  • Interface Arduino to low cost RF wireless modules to provide high performance transmitters, receivers and transceivers for data. Circuit diagrams and documentation and download instructions here.

• HT12E
  • HT12E is a 12-bit encoder IC suited for remote control applications. The serial stream generated by this IC can be transmitted via RF or infrared to an Arduino running a specific decoding library available at this source.

• X10 Wireless
  • Arduino interface to the CM17A "FireCracker". The CM17A is a "serial" dongle that sends RF signals to X10 receivers which in turn send signals down the house wiring to control lights and appliances. Documentation and code here.

• X10 Receiver
  • Arduino interface to the PSC05/TW523. The Arduino IDE includes the X10 library that lets you transmit. This example shows how to receive X10 commands. Documentation and code here.
  • Connect a SmartHomes module 1134B with the Arduino using the X10 protocol and X10 modules.

• Infrared
  • IR remote library for transmitting and receiving multiple infrared remote protocols.
  • dirt cheap wireless: serial communication via infrared light
  • Infrared remote receivers
  • Control your Arduino using an Infrared Remote and the IK38khz sensor

• HomeEasy
  • HomeEasy is a 433MHz AM based home automation range. Beginnings of instructions and code for using the Arduino with HomeEasy controllers and devices. (Work in progress.)

• HopeRF
  • Interface Arduino to HopeRF 433MHZ serial transceivers and other 'transparent' serial RF transceivers. Includes classes for node addressed, unreliable and reliable datagrams. Circuit diagrams, documentation and download instructions here.

• HopeRF RF12
  • The RFM12/RFM12B/RFM12BP modules for the 433/868/915 MHz frequency bands are connected via SPI. There's a driver for it here.

General

Arduino-related stuff that doesn't quite fit anywhere else.

• Hardware Abstraction libraries
• External 3V3 supply using an LM317 Schematic and board in Eagle format. Also a number of different trivial/helpful little things like Arduino-related Eagle Library, boards, and even an Arduino IDE "icon".
• Loomduino - Reduce the number of jumper wires you need by using ribbon cable to connect things to your Arduino (such as the 4D Picaso, VDIP1 and nRFL2401+).
• USBIZI as Arduino host
• Arduino and analog sensors: Proximity, Light, Force and Tilt detectors
• USBIZI as Arduino host
• Using an Arduino for access control. (Electronic "lock")