Uses a RF433Mhz component plugged on an Arduino to listen to signals and decode it.
Download a zip of this repository, then include it from the Arduino IDE.
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Arduino board. Tested with NANO and UNO.
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Radio Frequence 433Mhz RECEIVER like MX-RM-5V.
RF433 RECEIVER data pin must be plugged on a board' digital PIN that can trigger interrupts, that is, D2 or D3.
This RECEIVER PIN is defined at the time a 'Track' object is created. This library does not set it at compile time.
See file schema.fzz (Fritzing format) or schema.png, for a circuit example with receiver plugged on D2.
See examples/01_main/01_main.ino for an example. This main example will output information in a way that is ready to be used by the RF433recv library, see below why this can be interesting.
See examples/02_output-received-code/02_output-received-code.ino for another example.
See examples/03_output-signal-timings/03_output-signal-timings.ino for another example, with detailed signal timing information.
See examples/04_react_on_code/04_react_on_code.ino for an example with code check.
See examples/05_callback/05_callback.ino for an example with callback functions registered to be called when specific codes are received.
The library assumes one of the following auto-synchronization protocols (tiret for high signal, underscore for low radio signal):
Tri-bit __- versus _--
Tri-bit inverted -__ versus --_
Manchester _- versus -_
The decoder tries to be as flexible as possible to decode any protocols, without pre-knowledge about signal timings. To be generic enough, only the relationships between timings are analyzed, to deduct the 'short' and 'long' duration on 'low' and 'high' radio frequence signal value. No pre-defined timing is used.
Most often, 'long' is twice as long as 'short', and the durations on the low signal are the same as on the high signal, but this library doesn't assume it. 'long' are not necessarily twice as long as 'short', and the high signal timings can be totally different from the low signal timings.
The signal can also contain the below:
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A 'prefix' made of a first succession of 'low, high' durations that don't match short and long durations encountered later. Such a prefix has been seen on FLO/R telecommands, likely, to distinguish between FLO (fixed code) and FLO/R (rolling code).
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A 'sync' prefix made of a succession of low and high of the same duration. Note such a prefix could be regarded as Manchester encoding of as many '0' bits (when using RF433ANY_CONV0, see below). The library assumes that such a sequence, if seen at the beginning ('short' and 'long' durations are not yet known), corresponds to a synchronization prefix, not to a Manchester encoding of '0' bits.
The signal decoding can be done using two conventions. Switching from one convention to another for the same signal will simply invert bit values.
| Signal shape | RF433ANY_CONV0 | RF433ANY_CONV1 | |
|---|---|---|---|
| Tri-bit | low short, high long | 0 | 1 |
| Tri-bit | low long, high short | 1 | 0 |
| Tri-bit Inverted | high short, low long | 0 | 1 |
| Tri-bit Inverted | high long, low short | 1 | 0 |
| Manchester | low short, high short | 0 | 1 |
| Manchester | high short, low short | 1 | 0 |
RF433recv is found here: https://github.com/sebmillet/RF433recv
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RF433any has no pre-defined idea of the code to analyze (nature of encoding, code timings, number of bits).
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RF433recv works the other way round: it works with the exact code characteristics.
Then what is RF433recv good for?
Actually RF433any, while being 'easy and universal', consumes a lot of memory, and this can be problematic. RF433recv consumes much less memory, allowing to do something else!
How to get the best of the two worlds
You can use RF433any to get the exact code characteristics and re-use it with RF433recv library.
This is the goal of examples/01_main/01_main.ino
You can copy-paste the output of 01_main.ino to call RF433recv library.
Since RF433any is struggling to identify a coding sequence from any kind of signal, it is prone to identifying codes from what is noise.
There are two ways to mitigate it:
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Use get_nb_bits() (see example
01_main.ino) and ignore any signal below a certain threshold. Note RF433any has a hard-coded limit of 7 bits of coding. -
Use strictness of signal analyzis. That is, when creating the Track object, use the second parameter.
Default Track construction:
Track track(PIN_RFINPUT);This is equivalent to:
Track track(PIN_RFINPUT, RAIL_MOOD_LAXIST);If you are tired of fake receptions of actually non-coding signal, you can instead execute:
Track track(PIN_RFINPUT, RAIL_MOOD_STRICT);