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RF SPST switch

Discussion in 'Electronic Design' started by Viktor Ilijasic, Jul 13, 2006.

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  1. Greetz and apologies if I missed the proper group to ask this.

    I am looking for a circuit/scheme of a simple battery operated wireless
    switch, and cannot find it anywhere. I keep finding some complicated stuff
    that requires PIC programming and whatnot.

    I am an electronics amateur, but am pretty good with solder, so I need some
    instructions how to build the simplest switch that IS wireless, and DOES NOT
    require optical visibility. So, IR is out.

    My guess is that some simple RF transmitter/reciever could be built, but I
    lack the knowlege what exactly to build.

    My requirements are as follow:
    reciever shold be as small as possible
    batteries for the reciever too
    transmitter small if possible, if not, nevermind
    security not an issue, no special coding/128bit_encryption needed
    if possible some vanilla wire for an antenna
    range shold be enough to operate the thing through a couple of walls (20-30m
    indoor, hopefully 100m out)

    Is there anyone out there that can help me with my quest? :) Please? :)


  2. you are not trying to build an IED, are you?

  3. Arg! I had to look that acronym up in google. :)

    No, i'm not. I want a switch to power up a small LED light when I approach
    the tent or my car in the dark. :)

    Maybe activate some circuitry when i come home, have to think more about
    that part. That's why one of the requirements was two to three walls of

    Although, I admit, the application of this kind of switch could be very
    broad. :-/

    Oh, yes, and I asked for an on/off switch. Not just on. :)

    You know how to build one?

  4. Rich Grise

    Rich Grise Guest

    If you have anything like Radio Shack in your country, you could just
    buy a transmitter/receiver pair. I got a set once for about US$15.00,
    with a transmitter like a key fob, and the receiver used the exact same
    injection-molded plastic case as a coffee timer, but without the big
    knob on the front. ;-)

    Good Luck!
  5. There is something like Radio Shack...

    I know that it's possible to buy remote for mains power switch, dunno if
    there is a battery operated one.

    But I'd rather buy the components myself and build it myself. And would
    probably pay less that way. :-/


  6. Joerg

    Joerg Guest

    Hello Viktor,

    Years ago I have seen a camping lantern that came with an RF remote (!).
    Blew my mind, couldn't believe it, couldn't imagine why on earth they
    designed that. It was bought at a regular camping store.
  7. ehsjr

    ehsjr Guest

    You wouldn't pay less, and, given the way you described
    your skill level, it is likely wouldn't be able to build
    it yourself anyway. Get the Radio Shack or equivalent
    device. Or modify a cheap R/C setup to light the LED.
    Radio Shack sells something called a Zip-Zap - a small
    R/C car - that might be a good candidate. Maybe your
    Radio Shack equivalent sells something similar.

  8. Oh, c'mon, give me a break.

    I managed to build this:

    and this:

    and some other stuff that's not on the web.

    Leave it to me to decide what I can and what I cannot, thank you.

    Now, if you have something that could help me, I would be grateful.

  9. Why do people have motion sensors activated lights in their back and front

    My guess is so they could see their path and door when they approach, maybe
    where to stuck the key etc. What do you think?


  10. Security. They come on when someone enters an area they are not
    supposed to. The fact that they light your way is just an extra

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  11. Joerg

    Joerg Guest

    Hello Viktor,
    Not really. They think it increases security, and to some extent maybe
    it does. But you'd have to discount all those nights where everybody
    woke up "hooo, there's got to be a bad guy out there..." after the
    sensor was tripped by a bat or a cat.

    Seems everything is remote controlled these days. Some day even our
    foxes will probably demand cable TV and a remote...
  12. Joerg

    Joerg Guest

    Hello Viktor,

    One more idea just came to mind: Remote doorbells. We have one and the
    receiver in the bell operates from four D cells. They are in there since
    more than five years and still fine. These bells are cheap, about $20 in
    hardware stores (US). I don't know what it would be in your country
    (Hungary?). Maybe you can find a schematic on the web if you really want
    to build your own but unless you have most parts already there it's
    probably going to cost you more.

    The transmitters for these bells can be either of two things: A little
    box hooked up to the primary bell and thus low voltage AC powered
    (that's what we have) or a small transmitter with a coin cell (that's
    what you'd probably want).
  13. Rich Grise

    Rich Grise Guest

    I was at the bank today, and in the next line was a guy with a
    mini-telephone attached to his ear.

    All I can think of when I see those people apparently talking to
    themselves, is a strip in MAD Magazine, back in the '60's, when
    "transistor radios" were becoming so popular that kids of all ages
    were holding them up to their ear while walking down the street, so
    they could listen to their favorite station. In the strip, the author
    predicted that eventually, the human ear would evolve to hold the
    radio in place, so they could listen to the radio with hands-free!

    Odd, how prophetic satire can be sometimes. ;-)

  14. DaveM

    DaveM Guest

    Check out the remote control at
    It's pretty much exactly what you want, with a few options. Not a kit, but if I
    were looking for a simple remote control device, I'd definitely buy this.


    Dave M
    MasonDG44 at comcast dot net (Just substitute the appropriate characters in the

    They call it PMS because Mad Cow Disease was already taken.
  15. quietguy

    quietguy Guest

    What about grabbing one of those wireless doorbells that sell for <$10 and
    just modify the output so it does what you want

  16. ehsjr

    ehsjr Guest

    Viktor Ilijasic wrote:

    Ok, apologies if I misunderstood your description of
    your skill level.
    Well, I already did, but you didn't like it. So
    I'll try again with something different: kits.pdf

    You may be able to use the transmitter & receiver
    they offer, without the encoder and decoder. You decide.

  17. Croatia.

    Thanks for suggestions.

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