Hi

         What kind of receiver did you use for rfpics ?

Rubens




At 18:09 16/12/2004, you wrote:
>piclist-bounces@mit.edu wrote:
> > its been my experience with similar "simple" links that they get a
> > LOT of garbage in the signal.  The actual transmission goes through
> > just fine, but finding it in the garbage can be tough.  I had
> > moderate success using simple 4-byte "start" and "stop" codes.
>
>This has been my experience as well. Another thing to watch out for
>is continuous '1' or '0' bits, which can throw the receiver off.
>There's plenty discussion in the piclist archives about the reasons.
>
>I recently did a one-way radio link with the rfPICs. I based my code
>on the Microchip examples provided. Transmitter sends 16 bits of
>alternating '1' and  '0', with a length of 400usec. When the receiver
>detects alternating '1' and  '0' of the right length, it decides a
>transmission has started.
>
>I send a unique serial number along with the data. If the serial
>number matches, it decides the transmission was "probably" error
>free.
>
>A lot of transmissions got rejected by the receiver. Those that
>did get through were correct a majority of the time, but not all
>the time. In other words, sometimes the serial number was received
>correctly, but there was a bit error in the data. If I were to do it
>again, I'd add at least a checksum.
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