Read data from heart monitor via wireless...?

Goeytex

Senior Member
It might be an interesting project. You will need a good scope or logic analyzer as well a receiver or transceiver capable of demodulating the signal. My guess is that it might operate in the 2.4 GHz ISM band. The manuals are no help with the technical aspects of the signal.

I would probably start with a Nordic NRF24l01+ module ( Or Beken 2421) as a receiver and have it sweep through the channels looking for a valid preamble. Then go from there.
 

AllyCat

Senior Member
But do someone know how data packets are?
Hi,

My guess is "no".

Even to start, you really need a technical specification to tell you the radio frequency that it uses. In view of the (necessary) very low power and short range, I would guess it's the 434 MHz ISM band, or even much lower frequencies using "induction loop" principles. Once you know the carrier frequency, then you can perhaps start some "detective work" to identify the type of modulation and the data (packet) format. Not an easy task as many have discovered before.

Good luck, Alan.
 

Goeytex

Senior Member
Thanks to all for answers.
But do someone know how data packets are?
Probably not.

It's not likely that anyone will know the details of the data packet format except the manufacturer. And that information is certainly confidential. This is the reason for the scope or logic analyzer. You will need to figure it out by looking at the actual data assuming you can first determine the carrier frequency, modulation type, & RF data rate.

This is not something that can be done in few hours with no test equipment. Even with good test equipment it could take days to weeks to analyze the packet structure to the point that the transmission could be intercepted and decoded into valid data.
 

akard

New Member
Probably not.

It's not likely that anyone will know the details of the data packet format except the manufacturer. And that information is certainly confidential. This is the reason for the scope or logic analyzer. You will need to figure it out by looking at the actual data assuming you can first determine the carrier frequency, modulation type, & RF data rate.

This is not something that can be done in few hours with no test equipment. Even with good test equipment it could take days to weeks to analyze the packet structure to the point that the transmission could be intercepted and decoded into valid data.

Right considerations...
:)
 

hippy

Technical Support
Staff member
Looking at the PDF, is the SIGMA PC25.10 not just a receiver which processes data from a heart rate monitoring belt, not a transmitter in its own right ?

The belt looks a little like the one Polar offer and might even use the same transmission mechanism but perhaps not. I don't recall the Polar having a protocol per se, just a burst of 5kHz carrier for every heart beat, but there's a receiver module available that pulses per heart beat when receiving from the belt. Everything else has to be catered for by whatever interfaces to that.
 

akard

New Member
It seems that data trasmitted by chest belt is coded by an algorithm that immunize interferences.
There are not other informations...
some other help?
 

MFB

Senior Member
It may help to try and detect the belt transmissions with a scanning receiver. If successful, a scope on the output may be all you need to workout the form of modulation being used. Then you might start to consider how to demodulate and decode the output signal. Unless you can obtain full documentation for the transmitter, there is no easy route.
 
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