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@@ -29,13 +29,17 @@ how things work just grepping inside.
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In order to show unknown signals, the application attempts to understand if
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the samples obtained by the Flipper API (a series of pulses that are high
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or low, and with different duration in microseconds) look like belonging to
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-a legitimate signal, and aren't just noise. We can't make assumptions about
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+a legitimate signal, and aren't just noise.
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+
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+We can't make assumptions about
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the encoding and the data rate of the communication, so we use a simple
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but relatively effective algorithm. As we check the signal, we try to detect
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long parts of it that are composed of pulses roughly classifiable into
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a maximum of three different classes of lengths, plus or minus 10%. Most
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encodings are somewhat self-clocked, so they tend to have just two or
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-three classes of pulse lengths. However often pulses of the same theoretical
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+three classes of pulse lengths.
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+
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+However often pulses of the same theoretical
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length have slightly different lenghts in the case of high and low level
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(RF on or off), so we classify them separately for robustness.
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@@ -51,6 +55,14 @@ Under the detected sequence, you will see a small triangle marking a
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specific sample. This mark means that the sequence looked coherent up
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to that point, and starting from there it could be just noise.
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+In the bottom-right corner the application displays an amount of time
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+in microseconds. This is the average length of the shortest pulse length
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+detected among the three classes. Usually the *data rate* of the protocol
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+is something like `1000000/this-number*2`, but it depends on the encoding
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+and could actually be `1000000/this-number*N` with `N > 2` (here 1000000
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+is the number of microseconds in one second, and N is the number of clock
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+cycles needed to represent a bit).
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+
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Things to investigate:
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* Many cheap remotes (gate openers, remotes, ...) are on the 433.92Mhz or nearby and use OOK modulation.
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