Decoding On-Off-Keying Modulation to Binary

[Martin Mal]

Hi All!,

I didn't really know where else to post this, hoping for any helpful information.

I'm working with GNU Radio and am trying to decode a simple 433Mhz RF remote to its binary representation. The only info i found online is to do this with audacity, however i don't see why it cant be done in python, and RTL_433 does just that. Already tested with my device and received the correct signals. Tried to reverse engineer it, but was unable to translate to python using gnuradio blocks. 

Pretty much my flow chart used to extract the signal is RTL SDR Source -> Xlating filter -> AM Demod -> Resampler -> Audio Sink and Message Sink (I can hear the pulses). In python I read from the message sink, but i'm not really sure what data i'm getting (seems like gibberish and doesn't correlate to amplitude like i would expect). I was expecting to be able to compare the message to a threshold and pulse width to determine if it was a 1 or 0 and formulate a packet. 

I'm trying to do something really similar to Kevin @ https://github.com/kevinmehall/rtlsdr-433m-sensor/tree/91f9d4b5e9854eb0051e7e26e6a71b062251ffdf where he decodes an Oregon Scientific sensor. 

Pretty much the problem is being able to read output from my top_block.py, process it, and convert it to a packet. 

Specs on the device, 20 bit pulses, separated by 1ms per pulse. 20ms wide. 

I'll be watching this thread all day for any replies and i'll get respond asap, Gotta get this thing done in the next two day. I really don't think it's a hard problem to solve. If this isnt the correct place to post this, do anyone know someone i can get in contact with for help on the use of message sinks to decode an am signal. 

Best,

Martin

[Martin Mal]

For reference heres the output from rtl_433 in -a more, works great! Trying to do the same thing with gnuradio.

[Martin Mal]

So my approach was wrong, a clock recovery mm to binary slicer to a message sink is a much better solution. However I am still getting gibberish out of the binary slicer. Any tips? 

On Wednesday, April 13, 2016 at 1:02:23 PM UTC-4, Martin Mal wrote:

[Benjamin Larsson]

On 04/13/2016 07:02 PM, Martin Mal wrote:
> Hi All!,
>
> I didn't really know where else to post this, hoping for any helpful
> information.
>
> I'm working with GNU Radio

This is the wrong forum for GNU Radio questions, but maybe this will
help you:

https://www.youtube.com/watch?v=bKqiq2Y43Wg

MvH
Benjamin Larsson