IRremote Arduino Library

Available as Arduino library "IRremote"

Version 2.8.2 - work in progress

This library enables you to send and receive using infra-red signals on an Arduino.

Tutorials and more information will be made available on the official homepage.

Installation

Click on the LibraryManager badge above to see the instructions.

Supported IR Protocols

Aiwa, BoseWave, Denon, Dish, JVC, Lego, LG, MagiQuest, NEC, Panasonic, RC5, RC6, Samsung, Sanyo, Sharp, Sony, Whynter, (Pronto).
Protocols can be switched off and on by changing the lines in IRremote.h:

#define DECODE_<PROTOCOL_NAME>  1
#define SEND_<PROTOCOL_NAME>    1

Wiki

This is a quite old but maybe useful wiki for this library.

FAQ

IR does not work right when I use Neopixels (aka WS2811/WS2812/WS2812B)
Whether you use the Adafruit Neopixel lib, or FastLED, interrupts get disabled on many lower end CPUs like the basic Arduinos for longer than 50 µs. In turn, this stops the IR interrupt handler from running when it needs to. There are some solutions to this on some processors, see this page from Marc MERLIN
The default IR timer on AVR's is timer 2. Since the Arduino Tone library as well as analogWrite() for pin 3 and pin 11 requires timer 2, this functionality cannot be used simultaneously.
You can use multiple IR receiver by just connecting the output pins of several IR receivers together. The IR receivers use an NPN transistor as output device with just a 30k resistor to VCC. This is almost "open collector" and allows connecting of several output pins to one Arduino input pin.

Handling unknown Protocols

Disclaimer

This library was never designed to handle long codes like the ones used by air conditioners. See Recording long Infrared Remote control signals with Arduino.
The main reason is, that it was designed to fit inside MCUs with relatively low levels of resources and was intended to work as a library together with other applications which also require some resources of the MCU to operate.

Hints

If you do not know which protocol your IR transmitter uses, you have several choices.

Use the IRreceiveDumpV2 example to dump out the IR timing. You can then reproduce/send this timing with the IRsendRawDemo example. For long codes with more than 48 bits like from air conditioners, you can change the length of the input buffer in IRremoteInt.h.
The IRMP AllProtocol example prints the protocol and data for one of the 40 supported protocols. The same library can be used to send this codes.
If you have a bigger Arduino board at hand (> 100 kByte program space) you can try the IRremoteDecode example of the Arduino library DecodeIR.
Use IrScrutinizer. It can automatically generate a send sketch for your protocol by exporting as "Arduino Raw". It supports IRremote, the old IRLib and Infrared4Arduino.
To increase strength of sent output signal you can increase the current through the send diode, or use 2 diodes in series, since one IR diode requires only 1.5 volt. Changing IR_SEND_DUTY_CYCLE to 50 increases the signal current by 40%.

Compile options / macros for this library

To customize the library to different requirements, there are some compile options / macros available.
Modify it by commenting them out or in, or change the values if applicable. Or define the macro with the -D compiler option for global compile (the latter is not possible with the Arduino IDE, so consider to use Sloeber.

Name	File	Default value	Description
`DEBUG`	IRremote.h	disabled	Enables lots of lovely debug output.
`USE_NEC_STANDARD`	IRremote.h	disabled	Use LSB first, address/code schema for encoding.
`USE_NO_SEND_PWM`	IRremote.h	disabled	Use no carrier PWM, just simulate an active low receiver signal.
`USE_SOFT_SEND_PWM`	IRremote.h	disabled	Use carrier PWM generation in software, instead of hardware PWM.
`PULSE_CORRECTION_MICROS`	IRremote.h	3	If USE_SOFT_SEND_PWM, this amount is subtracted from the on-time of the pulses.
`USE_SPIN_WAIT`	IRremote.h	disabled	If USE_SOFT_SEND_PWM, use spin wait instead of delayMicros().
`RAW_BUFFER_LENGTH`	IRremoteint.h	101	Buffer size of raw input buffer. Must be odd!
`IR_SEND_DUTY_CYCLE`	IRremoteBoardDefs.h	30	Duty cycle of IR send signal.
`MICROS_PER_TICK`	IRremoteBoardDefs.h	50	Resolution of the raw input buffer data.

Modifying library properties with Arduino IDE

First use Sketch/Show Sketch Folder (Ctrl+K).
If you did not yet stored the example as your own sketch, then you are instantly in the right library folder.
Otherwise you have to navigate to the parallel libraries folder and select the library you want to access.
In both cases the library files itself are located in the src directory.

Modifying library properties with Sloeber IDE

If you are using Sloeber as your IDE, you can easily define global symbols with Properties/Arduino/CompileOptions.

Other IR libraries

Here you find a short comparison matrix of 4 popular Arduino IR libraries.
Here you find an ESP8266/ESP32 version of IRremote with an impressive list of supported protocols.

Supported Boards

Arduino Uno / Mega / Leonardo / Duemilanove / Diecimila / LilyPad / Mini / Fio / Nano etc.
Teensy 1.0 / 1.0++ / 2.0 / 2++ / 3.0 / 3.1 / Teensy-LC; Credits: @PaulStoffregen (Teensy Team)
Sanguino
ATmega8, 48, 88, 168, 328
ATmega8535, 16, 32, 164, 324, 644, 1284,
ATmega64, 128
ATmega4809 (Nano every)
ATtiny84, 85
SAMD21 (receive only)
ESP32
ESP8266 is supported in a fork based on an old codebase. It works well given that perfectly timed sub millisecond interrupts are different on that chip.
Sparkfun Pro Micro

We are open to suggestions for adding support to new boards, however we highly recommend you contact your supplier first and ask them to provide support from their side.

Hardware specifications

The timer and the pin usage can be adjusted in IRremoteBoardDefs.h

Board/CPU	IR-Send (PWM) Pin	Timers
ATtiny84	6	1
ATtiny85 > 1 MHz	1, 4	0, 1
ATmega8	9	1
ATmega48, ATmega88, ATmega168, ATmega328	3, 9	1, 2
ATmega1284	13, 14, 6	1, 2, 3
ATmega164, ATmega324, ATmega644	13, 14	1, 2
ATmega8535 ATmega16, ATmega32	13	1
ATmega64, ATmega128, ATmega1281, ATmega2561	13	1
ATmega8515, ATmega162	13	1
ATmega1280, ATmega2560	5, 6, 9, 11, 46	1, 2, 3, 4, 5
ATmega4809	5, 6, 9, 11, 46	TCB0
Leonardo (Atmega32u4)	5, 9, 13	1, 3, 4_HS
Zero (SAMD)	*, 9	TC3
ESP32	4, all pins	1
Sparkfun Pro Micro	5, 9	1, 3
Teensy 1.0	17	1
Teensy 2.0	9, 10, 14	1, 3, 4_HS
Teensy++ 1.0 / 2.0	1, 16, 25	1, 2, 3
Teensy 3.0 / 3.1	5	CMT
Teensy-LC	16	TPM1

Revision History

Please see changelog.md.

API documentation

See API reference in wiki.

To generate the API documentation, Doxygen, as well as Graphviz should be installed. (Note that on Windows, it may be necessary to add the Graphviz binary directory (something like C:\Program Files\Graphviz2.38\bin) to the PATH variable manually.) With Doxygen and Graphviz installed, issue the command doxygen from the command line in the main project directory, which will generate the API documentation in HTML format. The just generated api-doc/index.html can now be opened in a browser.

Why do we use 33% duty cycle

We do it according to the statement in the Vishay datasheet:

Carrier duty cycle 50 %, peak current of emitter IF = 200 mA, the resulting transmission distance is 25 m.
Carrier duty cycle 10 %, peak current of emitter IF = 800 mA, the resulting transmission distance is 29 m. - Factor 1.16 The reason is, that it is not the pure energy of the fundamental which is responsible for the receiver to detect a signal. Due to automatic gain control and other bias effects high intensity and lower energy (duty cycle) of the 38 kHz pulse counts more than high low intensity and higher energy.

BTW, the best way to increase the IR power is to use 2 or 3 IR diodes in series. One diode requires 1.1 to 1.5 volt so you can supply 3 diodes with a 5 volt output.
To keep the current, you must reduce the resistor by (5 - 1.3) / (5 - 2.6) = 1.5 e.g. from 150 ohm to 100 ohm for 25 mA and 2 diodes with 1.3 volt and a 5 volt supply.
For 3 diodes it requires factor 2.5 e.g. from 150 ohm to 60 ohm.

Contributing

If you want to contribute to this project:

Report bugs and errors
Ask for enhancements
Create issues and pull requests
Tell other people about this library
Contribute new protocols

Check here for some guidelines.

Contributors

Check here

Contact

Email: zetoslab@gmail.com Please only email me if it is more appropriate than creating an Issue / PR. I will not respond to requests for adding support for particular boards, unless of course you are the creator of the board and would like to cooperate on the project. I will also ignore any emails asking me to tell you how to implement your ideas. However, if you have a private inquiry that you would only apply to you and you would prefer it to be via email, by all means.

License

Up to the version 2.7.0 the License is GPLv2. From the version 2.8.0 the license is the MIT license.

iosifpeterfi/Arduino-IRremote