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Send Code #9

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Bihel29 opened this issue Jan 26, 2019 · 5 comments
Open

Send Code #9

Bihel29 opened this issue Jan 26, 2019 · 5 comments

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@Bihel29
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Bihel29 commented Jan 26, 2019

Hey, I have trouble understanding how to convert the received code to HEX

Example RTL_433 : https://i.imgur.com/IgBXTbH.png
Example SDR : https://i.imgur.com/UODlMsj.png

How to select the number of rows to send with CCmanager?

How to send "00111000 11111010 01110001 10001100 00000100" code with CCManager ?

How can I tell if the modulation is OOK, ASK or other?

It's hard for me to find information in my language.

Sorry for my bad english

Thanks

@jglim
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jglim commented Jan 26, 2019

Hello,

The SDRSharp screenshot looks very much like OOK where you were tuned at.

To see what FSK looks like, tune to your local FM radio frequencies. For AM radio, you may be able to see an example in the Airband frequencies without additional hardware

OOK is a subset of ASK, except that it switches between full power and zero power as a means of communicating.

I am unfamiliar with RTL433, however in the screenshot that you have uploaded, it seems to indicate that the data is 0x38,0xFA,0x71,0x8C,0x04. If you would like to send that many times in a row, you can add 0x00 to add an interval before your next transmission, for example 0x38,0xFA,0x71,0x8C,0x04,0x00,0x00,0x00,0x00,0x00,0x38,0xFA,0x71,0x8C,0x04,0x00,0x00,0x00,0x00,0x00,0x38,0xFA,0x71,0x8C,0x04,0x00,0x00,0x00,0x00,0x00,0x38,0xFA,0x71,0x8C,0x04,0x00,0x00,0x00,0x00,0x00,0x38,0xFA,0x71,0x8C,0x04

There is no timescale in your RTL433 log, so "Pulse Length 32" could be 32ms or 32μs (or something else). This is important as the baud rate (speed of transmission) is required to transmit correctly. For example, if each pulse takes 32ms, the baud rate will be 1 / (32/1000) which gives a value of 31.25

I would recommend taking a look at the guide

@Bihel29
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Bihel29 commented Jan 26, 2019

Thanks for your answer, I did not find the PDF it's more understandable now.

Do I have to use specific parameters for SDRSharp and/or Audacity?

Thank you

@jglim
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jglim commented Jan 28, 2019

Unfortunately I am not sure of which parameters you refer to; when I launch SDRSharp/Audacity, I use the default launch parameters.

@Bihel29
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Bihel29 commented Feb 5, 2019

Hey, thanks for your answer.

I have successfully decode your example with audacity: https://user-images.githubusercontent.com/11474337/32005448-9b4e8e7c-b9a4-11e7-9ff1-14d9ad040535.PNG

But when I try to decode another signal, I find it hard to determine which baud rate to use.

Do you have a tip or an example to give me?

Thanks

@jglim
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jglim commented Feb 5, 2019

I have tried to guess and annotate some hints. It would be helpful if you can upload the file that was open in that screenshot

32005448-9b4e8e7c-b9a4-11e7-9ff1-14d9ad040535-r

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