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Author Topic: Sniffing RAW wireless data (433MHz, 868MHz; FSK/ASK)  (Read 4118 times)
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Hello,

as the title suggests, I am interested into sniffing RAW data sent with 433MHz or 868MHz (i.e. ISM band). Modulation is either FSK or ASK.
Can you recommend any receiver to handle this issue, of course with Arduino!

Thank you very much.
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Modulation and demodulation are radio functions. They are not part of the data that is sent? What, exactly, are you trying to do.

I'd strongly recommend that you answer the question this time, or risk being shown the door.
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Thank you for the fast answer.
As far as I know, the receiver has to "know" in what type of modulation the signal was sent. And I know that the data can be sent via different types of modulation. At home, I have many devices that work with this properties (frequency and modulation type). For me, it is important to get the data they sent, at first the data, not necessarily the actual information. Then, I will try to work with it (what will get the harder part). If there are any questions left, feel free to ask.
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Quote
As far as I know, the receiver has to "know" in what type of modulation the signal was sent.
Perhaps I'm wrong, but I'd expect a FSK receiver to only operate with a FSK transmitter, and a ASK receiver to only operate with a ASK transmitter.

It seems to me that you are looking for receiver that can receiver transmissions from either type of transmitter. No idea whether such a critter exists.

The data that your devices send is modulated for transmission and demodulated on reception. The input to the sender and the output from the receiver are identical, regardless of what type of modulation was used.
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Perhaps I'm wrong, but I'd expect a FSK receiver to only operate with a FSK transmitter, and a ASK receiver to only operate with a ASK transmitter.
No, that's what I meant, too. Knowing the modulation meant for me to have the ability to demodulate the signal modulated with this type of modulation.

It seems to me that you are looking for receiver that can receiver transmissions from either type of transmitter. No idea whether such a critter exists.
Concerning this, I thought too. And I finally decided to use two devices for this issue. That means one receiver only works with FSK, the other one with ASK. So, I think you're right. It's difficult to find one. The only one, I found, is the ATA5811 - however it seems to be very sophisticated. That doesn't mean I have decided not to want to work with it.

So I will look for one ASK receiver and a FSK receiver separately. Can you recommend one that supports (only)one of these modulations?

They should be as simple as possible, the received data should be given directly at a pin output without trying to decode it.
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Hi,
I am pretty trying to do the same thing.
I live in Belgium and have several devices working wireless.
That for I bought a Jeenode boards, as long as its an arduino compatible board with an RF module integrated. (RFM12b FSK)

My aim was to sniff the sender to echo the orders when needed.
But it seems to be working with a rolling key, so that way to proceed is not going well.

At present I am trying to first run and my Jeenode is having some (hardware) issues du to my solder joins (?).

Where are you in your seeking process ??
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At first you have to know how the signal is transmitted. This includes
- Frequency
- Modulation
- Encoding

So both  the  last  points are about the protocol.

If it is rolling code you mostly still read the message.
Could you please describe what happens and which signal to capture?
And find out as much technical data about the transmitter as possible.

Additionally, I recommend some simple ASK Module from ebay which are very cheap (e.g. ebay nr 121017087078)
Or did you have already any successes with your procedure?
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Have a look at the CC1101, lots of cheap modules available, supports 2FSK, GFSK, 4FSK, ASK, OOK and MSK modulations, FEC, data whitening, manchester encoding and data rates ranging 0.6 - 500Kbps. However most modules only work at around 433MHz. For FSK modulations you will also need to know the frequency deviation. Bandwidth will also effect things, too narrow and it won't be able to pick up the entire transmission, too wide and it may pick up multiple transmissions.
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