Hi Dane,

good work! Especially the custom blocks.

Regarding 1.: I'm not 100% sure I understand what you mean. Could you
maybe elaborate on what you want to be able to do?

Regarding 2.: Since this really seems to be an FSK system, try using the
"Frequency Mod" block, fed (for now) from a vector source -> repeat ->
frequency mod


Hope that helps

Marcus

On 04/19/2017 09:36 PM, Dane Goodwin wrote:
> Hey all
>
> I'm new to SDR stuff, and am trying to learn as much as I can. As
> hands-on practice is best, I found a cheap and simple rf device to
> practice with. Specifically, this remote
> <http://www.grandviewscreen.com/pdf/manuals/Accessaries/1GD-868MnIII%28RF_Remote_Controller%29.pdf>.
>
> It transmits an (almost) static signal, which can be replayed using
> hackrf_transfer. Each button repeats the same signal, but with a
> counter which increments as long as you hold the button down. Each
> button transmits 12 bytes which include a preamble, sync word,
> command, said weird counter, and a null byte to signal the end of the
> transmission. As I understand, the data is fsk/nrz encoded, but I've
> included a screenshot of the waveform I see right after the Quadrature
> Demod block, so you can see what I see. From the doc, the baud rate is
> 2400.
>
> I'd like to create a software version of the remote, which transmits
> the same signals as the remote, but using GRC to encode the message
> properly. This is where I'm stuck, so, I'm asking for help with two
> things: 
> 1. How do you go about creating a qt gui source block which outputs
> something that GRC can use? What datatype should this block output?
>
> 2. How would I encode that output in such a way that it would be
> identical to what the remote transmits? I tried using the GFSK
> modulator with various settings, but that didn't work, and I'm not
> sure why.
>
> Regarding what I've done so far: I created a receiver for the remote
> in GRC. I used two custom blocks, so I've only attached a screenshot
> of the graph in this mail. The Pattern Dump block comes from here
> <https://github.com/tkuester/gr-reveng>, and basically looks for a
> given preamble, and passes the bits that follow to another block as a
> message. I wrote the receiver block, which checks those messages, and
> runs a different os command depending on what button was pressed.
>
> Thanks in advance for the help!
>
>
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