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@@ -5,12 +5,14 @@ implemented (and there are many proprietary ones, such as the ones in use
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in TPMS systems, car keys and many others), the curious person is left
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in TPMS systems, car keys and many others), the curious person is left
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wondering what the device is sending at all. Using ProtoView she or he can
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wondering what the device is sending at all. Using ProtoView she or he can
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visualize the high and low pulses like in the example image below
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visualize the high and low pulses like in the example image below
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-(showing a Volkswagen key in 2FSK):
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+(showing a TPMS signal produced by a Renault tire):
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This is often enough to make an initial idea about the encoding used
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This is often enough to make an initial idea about the encoding used
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-and if the selected modulation is correct.
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+and if the selected modulation is correct. For example, in the signal above
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+you can see a set of regular pulses used for synchronization and then
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+a sequence of bits encoded in [Manchester](https://en.wikipedia.org/wiki/Manchester_code) line code. If you study these things for five minutes, you'll find yourself able to decode the bits with naked eyes.
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## Decoding capabilities
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## Decoding capabilities
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@@ -26,11 +28,14 @@ Other than that, ProtoView is able to decode a few interesting protocols:
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The app implements a framework that makes adding and experimenting with new
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The app implements a framework that makes adding and experimenting with new
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protocols very simple. Check the `protocols` directory to see how the
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protocols very simple. Check the `protocols` directory to see how the
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-API works.
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+API works. The decoder receives the signal already converted into a bitmap,
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+where each bit represents a short pulse duration. Then there are functions
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+to seek specific sync/preamble sequences inside the bitmap, to decode
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+from different line codes, to compute checksums and so forth.
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## Reply capabilities
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## Reply capabilities
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-Once ProtoView decoded a given message, it is able to *resample* it
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+Once ProtoView decodes a given message, it is able to *resample* it
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in pulses and gaps of the theoretical duration, and send the signal again
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in pulses and gaps of the theoretical duration, and send the signal again
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via the Flipper RX capabilities. The captured signal can be sent
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via the Flipper RX capabilities. The captured signal can be sent
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to different frequencies and modulations than the ones it was captured
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to different frequencies and modulations than the ones it was captured
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antirez