Re: one channel radio frequency help

"robot guy" <huntin4jesus@xxxxxxxxx> wrote in news:1175634612.259231.224850
@p77g2000hsh.googlegroups.com:

Only problem is that the I don't know what was causing the device to
only respond to a certaing rate of speed from the flashing led. It was
all pre manufactured into a little sugur cube sized box

You had, likely, a typical IR reciever module from a VCR os the like. The
simply detect the presence of an IR signal oscillating at around 40 Khz,
and activate (pull to ground) the output pin at the presence of the 40Khz
IR signal. Your 555 was blinking the IR LED at the set frequency for that
module. A typical IR remote would modulate that carrier by turning it on
and off in the data pattern the remote creates.

RF remotes are similar, in that instead of a 40 Kz carrier on an IR LED,
the data pattern is directly modulates the transmitter. In theory, you
could do the the same, by gating an RF carrier, and detecting its presence,
but that is less than ideal. You should encode it, and depending on the
application, you should have a self error checking code.
.

Relevant Pages

  • Re: one channel radio frequency help
    ... simply detect the presence of an IR signal oscillating at around 40 Khz, ... A typical IR remote would modulate that carrier by turning it on ... RF remotes are similar, in that instead of a 40 Kz carrier on an IR LED, ... If you can bother you can find chips that do both the transmit and receive ...
    (sci.electronics.design)
  • Re: KFC goes to TEDs
    ... It is amazing how big their presence is and I think KFC has an exceptional ... out of her carrier. ... heartbeat which he says might tie in with thyroid problems in addition to ... I suggested that her fast heartbeat ...
    (rec.pets.cats.anecdotes)
  • Re: ssh command behavior
    ... Hopefull the presence of the tty on the remote won't cause ... Thanks Richard, that helped a lot! ...
    (comp.security.ssh)
  • Re: Network again!
    ... telnet: Unable to connect to remote host: Connection refused ... Check for presence of sshd: ... You checked for presence of sshd on your local machine. ... want to connect to the remote machine via ssh, you have to check it on the ...
    (Ubuntu)
  • Re: Number porting problem
    ... can't find any mention of a "presence number" however. ... remote call forwarding) where they play a message to callers giving my ...
    (uk.telecom)