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Protocols can be switched off and on by definining macros before the line `#incude <IRremote.h>` like [here](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/examples/SimpleReceiver/SimpleReceiver.ino#L14):
- Just remove the line `IRrecv IrReceiver(IR_RECEIVE_PIN);` and/or `IRsend IrSender;` in your program, and replace all occurrences of `IRrecv.` or `irrecv.` with `IrReceiver`.
- Since the decoded values are now in `IrReceiver.decodedIRData` and not in `results` any more, remove the line `decode_results results` or similar.
- Like for the Serial object, call [`IrReceiver.begin(IR_RECEIVE_PIN, ENABE_ED_FEEDBACK);`](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/examples/IRreceiveDemo/IRreceiveDemo.ino#L38) or `IrReceiver.begin(IR_RECEIVE_PIN, DISABLE_LED_FEEDBACK);` instead of the `IrReceiver.enableIRIn();` or `irrecv.enableIRIn();` in setup().
- Old `decode(decode_results *aResults)` function is replaced by simple `decode()`. So if you have a statement `if(irrecv.decode(&results))` replace it with `if (IrReceiver.decode())`.
- The decoded result is now in in `IrReceiver.decodedIRData` and not in `results` any more, therefore replace any occurrences of `results.value` and / or `results.decode_type` (and similar) to `IrReceiver.decodedIRData.decodedRawData` and / or `IrReceiver.decodedIRData.decodedRawData`.
- Overflow, Repeat and other flags are now in [`IrReceiver.receivedIRData.flags`](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/src/IRremote.h#L126).
- Seldom used: `results.rawbuf` and `results.rawlen` must be replaced by `IrReceiver.decodedIRData.rawDataPtr->rawbuf` and `IrReceiver.decodedIRData.rawDataPtr->rawlen`.
- The old functions `sendNEC()` and `sendJVC()` are deprecated and renamed to `sendNECMSB()` and `sendJVCMSB()` to make it clearer that they send data with MSB first, which is not the standard for NEC and JVC. Use them to send your **old 32 bit IR data codes**.
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 <20>s.
this functionality cannot be used simultaneously. You can use tone() but after the tone has stopped, you must call `IrReceiver.start()` or better `IrReceiver.start(<microsecondsOfToneDuration>)` to restore the timer settings for receive.<br/>
For applications only requiring NEC protocol, there is a receiver which has very **small codesize of 500 bytes and does NOT require any timer**. See the MinimalReceiver and IRDispatcherDemo example how to use it.
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](https://www.analysir.com/blog/2014/03/19/air-conditioners-problems-recording-long-infrared-remote-control-signals-arduino).<br/>
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.
For **long codes** with more than 48 bits like from air conditioners, you can **change the length of the input buffer** in [IRremote.h](src/IRremoteInt.h#L36).
- The [IRMP AllProtocol example](https://github.com/ukw100/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](https://github.com/bengtmartensson/Arduino-DecodeIR/blob/master/examples/IRremoteDecode/IRremoteDecode.ino) of the Arduino library [DecodeIR](https://github.com/bengtmartensson/Arduino-DecodeIR).
- Use [IrScrutinizer](http://www.harctoolbox.org/IrScrutinizer.html).
It can automatically generate a send sketch for your protocol by exporting as "Arduino Raw". It supports IRremote,
the old [IRLib](https://github.com/cyborg5/IRLib) and [Infrared4Arduino](https://github.com/bengtmartensson/Infrared4Arduino).
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 using [Sloeber](https://eclipse.baeyens.it).
| `EXCLUDE_EXOTIC_PROTOCOLS` | Before `#include <IRremote.h>` | disabled | If activated, BOSEWAVE, MAGIQUEST,WHYNTER and LEGO_PF are excluded in `decode()` and in sending with `IrSender.write()`. Saves up to 900 bytes program space. |
| `MARK_EXCESS_MICROS` | Before `#include <IRremote.h>` | 20 | MARK_EXCESS_MICROS is subtracted from all marks and added to all spaces before decoding, to compensate for the signal forming of different IR receiver modules. |
- [ESP8266 is supported in a fork](https://github.com/crankyoldgit/IRremoteESP8266) based on an old codebase. It works well given that perfectly timed sub millisecond interrupts are different on that chip.
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.
The receiver sample interval is generated by a timer. On many boards this must be a hardware timer, on some a software timer is available and used.<br/>
Every pin can be used for receiving.<br/>
The send PWM signal is by default generated by software. **Therefore every pin can be used for sending**.
## Hardware-PWM signal generation for sending
If you define `SEND_PWM_BY_TIMER`, the send PWM signal is generated by a hardware timer. The same timer as for the receiver is used.
but this depends on the receiver circuit in use. Most protocols use multiples of one time-unit for marks and spaces like e.g. [NEC](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/src/ir_NEC.cpp#L50). It's easy to be off-by-one with the last bit, since the last space is not recorded by IRremote.
If your protocol supports address and code fields, try to reflect this in your api like it is done in [`sendNEC(uint16_t aAddress, uint8_t aCommand, uint_fast8_t aNumberOfRepeats, bool aIsRepeat)`](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/src/ir_NEC.cpp#L86) and [`decodeNEC()`](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/src/ir_NEC.cpp#L145).<br/>
A detailed description can be found in the [ir_Template.cpp](https://github.com/Arduino-IRremote/Arduino-IRremote/blob/master/src/ir_Template.cpp#L18) file.
We do it according to the statement in the [Vishay datasheet](https://www.vishay.com/docs/80069/circuit.pdf):
- 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.<br/>
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.<br/>
For 3 diodes it requires factor 2.5 e.g. from 150 ohm to 60 ohm.
[Here](https://github.com/crankyoldgit/IRremoteESP8266) you find an **ESP8266/ESP32** version of IRremote with an **[impressive list of supported protocols](https://github.com/crankyoldgit/IRremoteESP8266/blob/master/SupportedProtocols.md)**.
## This is a short comparison and may not be complete or correct
I created this comparison matrix for [myself](https://github.com/ArminJo) in order to choose a small IR lib for my project and to have a quick overview, when to choose which library.<br/>
It is dated from **03.02.2021**. If you have complains about the data or request for extensions, please send a PM or open a discussion.
| Number of protocols | **50** | Nec + Panasonic + Hash \* | 12 + Hash \* | 17 + Hash \* | NEC |
| 3.Party libs needed| % | PinChangeInterrupt if not pin 2 or 3 | % | % | % |
| Timing method receive | Timer2 or interrupt for pin 2 or 3 | **Interrupt** | Timer2 or interrupt for pin 2 or 3 | Timer2 or interrupt for NEC | **Interrupt** |
| Timing method send | PWM and timing with Timer2 interrupts | Timer2 interrupts | Timer2 and blocking wait | PWM with Timer2 and blocking wait with delayMicroseconds() | % |
| Send pins| All | All | All ? | Timer dependent | % |
| FLASH usage (simple NEC example with 5 prints) | 1820<br/>(4300 for 15 main / 8000 for all 40 protocols)<br/>(+200 for callback)<br/>(+80 for interrupt at pin 2+3)| 1270<br/>(1400 for pin 2+3) | 4830 | 1770 | **900** |
| Remarks | Decodes 40 protocols concurrently.<br/>39 Protocols to send.<br/>Work in progress. | Only one protocol at a time. | Consists of 5 libraries. **Project containing bugs - 45 issues, no reaction for at least one year.** | Decoding and sending are easy to extend.<br/>Supports **Pronto** codes. | Requires no timer. |
\* The Hash protocol gives you a hash as code, which may be sufficient to distinguish your keys on the remote, but may not work with some protocols like Mitsubishi
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.
