need help selecting a transmitter and reciever

I once got a little tranmitter/receiver pair at Radio Shlock -  the
Xmtr was like a key fob, and the receiver was a plug-in box about
the size of a coffee timer; that could be adapted.

Good Luck!
Rich

On Tue, 21 Oct 2008 06:50:15 -0700 (PDT), panfilero


http://www.futurlec.com/Radio.shtml

These are very easy to use. Use a 4066, and drive it with the
receiver.

Regards,
 Bob Monsen

Thanks, do you know if I buy this... do I need to buy something called
a encoder and decoder?

On Wed, 22 Oct 2008 13:14:18 -0700 (PDT), panfilero


The encoder chip will ensure that you are only getting signals from
the sender, and not from some other stray 415MHz signal. If you don't
really care about that, you can just use the output as is. I used one
of these to run a servo once. No encoder, just the tx and rx pair, and
it worked quite well.

Regarding the 4066, you can't use it to switch signals outside the Vcc
to Vss range. So, use a blocking capacitor, and then bias it into the
middle of the range with two 100k resistors, one to Vss, one to Vcc.
Then switch it. After this, use another cap to bring it back down to
earth...

Note that you can only switch signals with this arrangement. If you
are trying to switch a speaker, it won't work well, since the 4066 has
pretty high resistance when it is on. There are newer switches that
have much lower resistance.

Regards,
 Bob Monsen

On Tue, 21 Oct 2008 10:13:59 -0700, Jim Thompson


Glad to help. BTW, I like futurlec, but they are sloooow... you might
be able to get these things at digikey or arrow, and have them ship in
this century :)

Regards,
 Bob Monsen

As has already been pointed out, you can't get "every" time.  Your
"minimum delay ... instant" requirement makes it tougher (although if
you're talking about people in the loop 50ms is going to be
imperceptible to all but the most perceptive users, and 20ms is probably
safe for all but the Flash -- and he can just lump it).

Just any old consumer-grade tx/rx pair is likely _not_ going to cut the
mustard, but I suspect that with a good receiver (you _can_ plug the
receiver into the wall, right?) you can make this work, even with a key
fob transmitter.

So, as Jan already said, tell us what you're _really_ doing.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

If you are wanting something like a remote-control ventriloquist
dummy, then you don't really need that kind of speed. But, regardless,
you might get by with taking apart a remote-control toy car.  Not the
better kind with proportional control, but the really cheap kind that
only has a few buttons. Then, you can cut the wires to the motors and
use them for your control.  But, you will need some electronics
knowledge so that you stay within the current and voltages you have
available need.

Alternatively,  is a source for a keyfob-style remote control kit.
The link for the keyfob itself has listings for PDF's of the manuals,
but the links aren't working.  I have not used this, and have no idea
if you can get the momentary output or speed that you need.
http://www.kitsusa.net/phpstore/html/Remote-Control-Unit-Kits-35-1.html

I've seen similar kits elsewhere.

Joe Dunfee

Thanks for the Suggestion

I don't know much (hardly anything) about this stuff.... some
transmitter/reciever modules seem to come with encoder/decoder chips
also.... are those required?  I'm having a hard time finding just
straight information on this stuff online.... just like.... reciever/
tranciever basics... like... what's an encoder/decoder....

I'm not going to control a ventriliquist thing... but what I want to
be able to do is control an audio signal.... so when I push the
button, then 10 feet away an audio signal will pass through my switch,
but I have to be able to push the button and hear the audio at the
same time.... which means I can afford some delay as long as its not
perceptible to humans.... but I gotta be able to hit the button at
least 10 times a second and get good tracking on that.... 10 times a
second seems slow when talking about electronics, no?

this kinda brings up another question that I was wondering about... if
I'm using a switch like the 4066, and the audio signal swings into the
negative... is that ok? The chip says it handles analog signals no
problem... but I don't know if my signal (which is in millivolts)
would pass through ok if it has a negative swing... which it does


much thanks!

Have you tried this bit? How good were you?

Deep

No but with two fingers I bet I could hit 20Hz

bcf93d75e7fb@w39g2000prb.googlegroups.com:


Bet you couldn't! >:)
Think through what you need carefully. If it was really something widely
needed, you'll find plenty of sources. And if it's NOT, then it's that much
more important to be as accurate as possible because you won't get the right
design otherwise. If you end up specifying 100 times the precision than a
carefull examination proves you need, the cost might rise beyond simple shock
value.

As people ALWAYS ask, sooner rather than later, what EXACTLY are you trying
to do? The less evasive you are, the more people can help you (and the less
likely thet are to think you want to reliably trigger a bomb...)

In the past I've seen blister pack wireless door bells at walmart
for ~$10.

On Tue, 21 Oct 2008 06:50:15 -0700 (PDT), panfilero