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one channel radio frequency help

R

robot guy

Jan 1, 1970
0
I could use some input on this subject. A while ago I used infared
led's hooked up to a 555 to flash at a certain speed, I can't remember
what speed it was but I then had some special little divice that when
it saw an infared flashing at one specific givin speed it would either
close a switch completing the circuit, I can't quite remember how I
wired it but any way I'd like to do the same with a radio. What I want
it to do is turn on and led first than move on to turning on ovens,
unlocking cars etc...
I have a good idea how to do it, just take a transmiter and pulse it
at a certain speed with a 555 but how do I get my reciever to only
regonize that certain speed, a filter, a tone detector? I could really
use some input or websites to look at.
 
R

Rich Grise, Plainclothes Hippie

Jan 1, 1970
0
I could use some input on this subject. A while ago I used infared
led's hooked up to a 555 to flash at a certain speed, I can't remember
what speed it was but I then had some special little divice that when
it saw an infared flashing at one specific givin speed it would either
close a switch completing the circuit, I can't quite remember how I
wired it but any way I'd like to do the same with a radio. What I want
it to do is turn on and led first than move on to turning on ovens,
unlocking cars etc...
I have a good idea how to do it, just take a transmiter and pulse it
at a certain speed with a 555 but how do I get my reciever to only
regonize that certain speed, a filter, a tone detector? I could really
use some input or websites to look at.

Make it up from scratch again, just like you did the first time, as you
seem to indicate[1]; and this time, if you're too drunk or zoned to
remember, take notes. For that matter, take notes anyway.

And always remember the first tenet of "State-Dependent Learning":
"If you can't learn it while you're high, you can't learn it."

And, just because I'm feeling frisky at this moment in spacetime, I
feel like ripping off one of Uncle Jimbo's lines: "Kids, there's a
time and a place for everything, and that's College!"

Have Fun!
Rich
[1]: "A while ago I used infared led's hooked up to a 555 to flash at a
certain speed ..."
[1A]: "I can't quite remember how I wired it..."
 
R

robot guy

Jan 1, 1970
0
I could use some input on this subject. A while ago I used infared
led's hooked up to a 555 to flash at a certain speed, I can't remember
what speed it was but I then had some special little divice that when
it saw an infared flashing at one specific givin speed it would either
close a switch completing the circuit, I can't quite remember how I
wired it but any way I'd like to do the same with a radio. What I want
it to do is turn on and led first than move on to turning on ovens,
unlocking cars etc...
I have a good idea how to do it, just take a transmiter and pulse it
at a certain speed with a 555 but how do I get my reciever to only
regonize that certain speed, a filter, a tone detector? I could really
use some input or websites to look at.

Make it up from scratch again, just like you did the first time, as you
seem to indicate[1]; and this time, if you're too drunk or zoned to
remember, take notes. For that matter, take notes anyway.

And always remember the first tenet of "State-Dependent Learning":
"If you can't learn it while you're high, you can't learn it."

And, just because I'm feeling frisky at this moment in spacetime, I
feel like ripping off one of Uncle Jimbo's lines: "Kids, there's a
time and a place for everything, and that's College!"

Have Fun!
Rich
[1]: "A while ago I used infared led's hooked up to a 555 to flash at a
certain speed ..."
[1A]: "I can't quite remember how I wired it..."

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.
 
L

Luhan

Jan 1, 1970
0
I could use some input on this subject. A while ago I used infared
led's hooked up to a 555 to flash at a certain speed, I can't remember
what speed it was but I then had some special little divice that when
it saw an infared flashing at one specific givin speed it would either
close a switch completing the circuit, I can't quite remember how I
wired it but any way I'd like to do the same with a radio. What I want
it to do is turn on and led first than move on to turning on ovens,
unlocking cars etc...
I have a good idea how to do it, just take a transmiter and pulse it
at a certain speed with a 555 but how do I get my reciever to only
regonize that certain speed, a filter, a tone detector? I could really
use some input or websites to look at.

I did something like this once to unlock my car and house by just
walking up to them. It used a PIC for the sending unit banging out a
very short code pulse about once a second and then going back to
sleep.

It worked great 'on the bench' and totally failed in any bright
daylight.

Luhan
http://mondo-technology.com
 
S

Stanislaw Flatto

Jan 1, 1970
0
robot said:
I could use some input on this subject. A while ago I used infared
led's hooked up to a 555 to flash at a certain speed, I can't remember
what speed it was but I then had some special little divice that when
it saw an infared flashing at one specific givin speed it would either
close a switch completing the circuit, I can't quite remember how I
wired it but any way I'd like to do the same with a radio. What I want
it to do is turn on and led first than move on to turning on ovens,
unlocking cars etc...
I have a good idea how to do it, just take a transmiter and pulse it
at a certain speed with a 555 but how do I get my reciever to only
regonize that certain speed, a filter, a tone detector? I could really
use some input or websites to look at.
Look at garage door openers, they use coder (usually set with bank of
swithes) in transmitter AND receiver. When those two codes match an
action is performed. But you have to have different music for every item
that you want to respond to your orders.

Something to do.

HTH

Stanislaw
 
G

Gary Tait

Jan 1, 1970
0
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.
 
J

joseph2k

Jan 1, 1970
0
Gary said:
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.
If you can bother you can find chips that do both the transmit and receive
functions for IR or RF remotes. They are typically marketed in transmit -
receive pairs. There are usually inexpensive ceramic resonators to
generate master clock frequencies for both parts.
 
G

Gary Tait

Jan 1, 1970
0
If you can bother you can find chips that do both the transmit and
receive functions for IR or RF remotes. They are typically marketed
in transmit - receive pairs. There are usually inexpensive ceramic
resonators to generate master clock frequencies for both parts.
--

Nowadays though, the system controller of the device being controlled
decodes the data coming from the IR or RF receiver, rather than a
standalone decoder IC.
 
J

joseph2k

Jan 1, 1970
0
Gary said:
Nowadays though, the system controller of the device being controlled
decodes the data coming from the IR or RF receiver, rather than a
standalone decoder IC.
I was talking about the transmitter and receiver IC's themselves. Even in
my very old designs the decision on what actions to take were made by a
micro that defined the application.
 
G

Gary Tait

Jan 1, 1970
0
I was talking about the transmitter and receiver IC's themselves.
Even in my very old designs the decision on what actions to take were
made by a micro that defined the application.

Well, for typical IR remotes, and basic non-secure RF remotes, they use
more or less a complex logic device, or even a real low end micro. They
directly provide a signal to drive an IR LED (through a drive
transistor), or gate an RF transmitter, which is typically one or two
trasnistors, a coil or SAW filter, and a board or wire antenna.

In context, if you are talking of a raw IR transmitter (the logical
other end of the IR receiver/decoder module) there is no ready made
modules of those, I know of, as those, as said, are driven from the
remote IC, in typical consumer remotes.

I do know there are "enclosed" radio transmitter/receiver modules. one
could use, but typical mass manufacturers build their own "on board".
 
J

joseph2k

Jan 1, 1970
0
Gary said:
Well, for typical IR remotes, and basic non-secure RF remotes, they use
more or less a complex logic device, or even a real low end micro. They
directly provide a signal to drive an IR LED (through a drive
transistor), or gate an RF transmitter, which is typically one or two
trasnistors, a coil or SAW filter, and a board or wire antenna.

In context, if you are talking of a raw IR transmitter (the logical
other end of the IR receiver/decoder module) there is no ready made
modules of those, I know of, as those, as said, are driven from the
remote IC, in typical consumer remotes.

I do know there are "enclosed" radio transmitter/receiver modules. one
could use, but typical mass manufacturers build their own "on board".

Damn, you are hard headed. You made me google for you. Feed "IR
transmitter IC" to google and get this, among other things on the first
page, "SDA2208-2 Siemens IR Remote Control TX/RX Driver, TV IC". Then you
toss that to google.
 
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