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Topic: 433Mhz tempreture and humidity sensor encoding? (Read 1 time) previous topic - next topic

soudrug

Hi,
as many others here I would like also read data from the remote temperature and humidity sensor, http://www.garni-meteo.cz/cz/eshop/bezdratova-cidla-a-nahradni-dily/pridavna-cidla/57-ts33-f.html  used in my home "meteorological" station.

It sends 3 packets of data each 45s. The sample I've created using Audacity shows one of them (the second graph is a clock waveform I've tried to derive from data).
.

I've got stuck with decoding binary data from the received sample. I tried simple decoding by assigning "1" to long pulse and "0" to short one, and vice versa, but I didn't find any match of data that was measured. But I didn't really expected to get results here. There is obviously some encoding used, as low pulses have also different length. I've already searched the forum and found that these gadgets sometimes uses Manchester encoding, but I according to Manch. encoding description, the first high pulse should be short and change of data occurs in the middle of clock period.

I know there is a lot of smart and experienced experts here, so, please, could you advice me what type of encoding could be used so I can continue with decoding?
Thanks.
 







Erdin

Perhaps you can open it, and try to see if an encoder chip is used.
The protocol can be analyzed on the PC with the Protocol Analyzer, http://wiki.nethome.nu/doku.php/analyzer/start

Riva

Can you attach a full audio sample here with what temperature/humidity the device was reading at the time. To me it does not look like Manchester encoding but I need to see the full sample with expected data to be sure. Elsewhere I have written a simple program to extract the bit patterns but I need a few values pre-setting so it can determine 0 & 1 bit lengths, sync length (assuming this uses one) and number of bits per packet.

soudrug

#3
Feb 20, 2013, 09:36 pm Last Edit: Feb 20, 2013, 10:29 pm by soudrug Reason: 1
Hi,
the recorded sample from Audacity is here.
Data from the sensor are at 0:31.5, where the measurement was 8.9°C,23% and at 1:16.5, where it measured 9.9°C,21%.

Erdin: The app looks good, I didn't know such tool exists.

Thanks.


Riva

Did you forget to include the Audacity project file? There are 14 sample files and no way to know what one corresponds to the data you supplied.

soudrug

Yes, sorry. The zip archive is fixed now..

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