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newbie question

V

voodoochile

Jan 1, 1970
0
Hi guys,

I wonder if anyone can help me with this simple problem I have as art of my
school project..

I am trying to turn an electrical current on and off down a wire via a
wireless signal on a key fob.

The cable is connected to a light. All I need to do is switch it on and
off -remotely.
Yes, I have seen remote light dimmers, but all I need to do is switch the
light on and off (not dim) and make the circuit as cheap and easy as
possible.

Can anyone tell me what the simple circuit diagram should look like, and
what components need to be on the pcb etc?

Plus if anyone can - what the circuit in the key fob should look like.
 
L

Lostgallifreyan

Jan 1, 1970
0
Hi guys,

I wonder if anyone can help me with this simple problem I have as art
of my school project..

I am trying to turn an electrical current on and off down a wire via a
wireless signal on a key fob.

The cable is connected to a light. All I need to do is switch it on
and off -remotely.
Yes, I have seen remote light dimmers, but all I need to do is switch
the light on and off (not dim) and make the circuit as cheap and easy
as possible.

Can anyone tell me what the simple circuit diagram should look like,
and what components need to be on the pcb etc?

Plus if anyone can - what the circuit in the key fob should look like.

If you can't do it already, how do you justify your insistence that it is
simple?

Does it have to be secure from misfiring from other sources of signals?
Does it have to work round corners or through walls, or are you ok with
line-of-sight?

And JeffM, you're a moron, I have some sympathy with your reason for
posting but all you seem to do is show up like a dumb policeman. Some
things are worth it, like that apparently deliberate attenpt to infect
people with Redlof virus in that other post, but if you're going to slap a
newcomer in the face you might at least offer something contructive and on
topic. You didn't even suggest he might cross-post instead of multipost,
let alone have something to say about his subject.
 
V

voodoochile

Jan 1, 1970
0
Thanks for the support.

Yes the device is okay with line of sight.
..
 
W

William P.N. Smith

Jan 1, 1970
0
voodoochile said:
I am trying to turn an electrical current on and off down a wire via a
wireless signal on a key fob.

The cable is connected to a light. All I need to do is switch it on and
off -remotely.
Yes, I have seen remote light dimmers, but all I need to do is switch the
light on and off (not dim) and make the circuit as cheap and easy as
possible.

We need more details, what voltage, what current, and (as 'lost'
pointed out) how robust it needs to be.

It sounds like this is something you have to build yourself, is that
true? If not, there are lots of car alarm systems with keyfobs, and
Radio Shack used to sell X-10 switches with small (RF) remotes.

Lots of ideas come to mind, 40KHz IR remote receivers, photocells,
etc, but I cna't tell from here how applicable any of them are.
 
E

Eeyore

Jan 1, 1970
0
William P.N. Smith said:
Hey, didn't you just say that in some other newsgroup?

Yes - he went and multi-posted his msg.

Ironic really.

Graham
 
L

Lostgallifreyan

Jan 1, 1970
0
Thanks for the support.

Yes the device is okay with line of sight.

Ok I'll make the starting assumption that this is an educational thing to
be a proof of concept, so the simplest possible answer is ok, you can see
its weaknesses and move to better ideas from there.

(Btw, if you reply like this, below the quoted text, it's clearer. Unlike
email, many people might answer, so this way it's clearer to read from top
down.)

If you're switching a light, you can maybe get away with using light itself
as a switch if the main light does not flood your sensor. The keyfob in
this case need have nothing but a baterry, a switch, a resitor and an LED
chosen for narrow viewing angle and high brightness. The sensor would be a
phototransistor (to save you needing another transistor as a gain stage)
with a coloured filter over the front to match the wavelength of your LED.
The phototransistor output would trigger a bistable circuit to latch the
off/on state, and output to a triac to control the lamp current. (That's
assuming it's mains current you're switching, which could be a wrong
assumption for a basic educational project, but never mind..)

Once you look for better ideas you'll want a pulse coded signal to
eliminate false trigerring, or radio to allow indirect signal paths. Either
of these are best handled with dedicated IC's, and I have no idea if this
is permissible in your project. If it's required that you fully understand
the logic and the part's behaviour, you might be better sticking to designs
that use discrete components not IC's. If you figure out a neat way
yourself, you'll learn more and probably get better grades from examiners,
so long as you don't overlook standard methods already available to you.
 
W

William P.N. Smith

Jan 1, 1970
0
Lostgallifreyan said:
The keyfob in
this case need have nothing but a baterry, a switch, a resitor and an LED
chosen for narrow viewing angle and high brightness.

Aka: A Flashlight. 8*)
 
L

Lostgallifreyan

Jan 1, 1970
0
Aka: A Flashlight. 8*)

Yep :) They even make those in keyfobs, is what made me think of it.. Very
nice simple idea. Does need the narrow beam though, and the narrowband
light. That way you can use the intensity of the narrow waveband and a
suitable colur filter to displace some of the difficulty of making filters
in electronics. The main problem is that you'd need a very narrowband
dichroic filter to make the simple idea effective beyond proof of concept,
and that's costly, and more about optics than electronics.
 
M

Michael A. Terrell

Jan 1, 1970
0
Eeyore said:
Yes - he went and multi-posted his msg.

Ironic really.

Graham


No, he MULTI-REPLIED. There is a subtle difference.


--
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
 
M

Michael Black

Jan 1, 1970
0
Don said:
How subtle is it when the reply as actually a new original post?
Actually, he is replying to the existing post, the reference line
does list the original message ID.

But, he doesn't keep the original subject in the header, so it
can look like he's starting new threads. I find that annoying, at
the very least because it's not immediately clear which post he
is replying to. I thought the proper way of doing it was to
put in a new subject, but include the old, such as
Spam (was: newbie question)
or something to that effect.

Then one knows the original thread just by looking at the subject
header, and it's clear he is making a point about the original post
rather than just posting nonsense (that it can look like to those
who are unaware of what he's doing). I think it's also clearer about
what's gong on. Announcing that something is spam or shouldn't be
cross-posted, well it's too late for the original post. But it
might help the newcomers, at least the ones who actually read
the newsgroups before posting, because then they'd learn that
such practices are at the very least frowned upon. Otherwise,
it's too easy for them to take the bad practices of some as example.

If someone wants to punish the original poster, then it can all
be done simply by reporting him. The point of making it public
is to try to limit further practice by others, and I don't think
the removal of the original subject from the reply helps
this process.

He's also be in a far better position when he's announcing
spam if he included a link to Mark Zenier's guide to the hierarchy,
ftp://ftp.eskimo.com/u/m/mzenier/seguide9706.txt
because that well explains where ads are supposed to go.

Michael
 
D

Don Bowey

Jan 1, 1970
0
Actually, he is replying to the existing post, the reference line
does list the original message ID.

But, he doesn't keep the original subject in the header, so it
can look like he's starting new threads. I find that annoying, at
the very least because it's not immediately clear which post he
is replying to. I thought the proper way of doing it was to
put in a new subject, but include the old, such as
Spam (was: newbie question)
or something to that effect.

Then one knows the original thread just by looking at the subject
header, and it's clear he is making a point about the original post
rather than just posting nonsense (that it can look like to those
who are unaware of what he's doing). I think it's also clearer about
what's gong on. Announcing that something is spam or shouldn't be
cross-posted, well it's too late for the original post. But it
might help the newcomers, at least the ones who actually read
the newsgroups before posting, because then they'd learn that
such practices are at the very least frowned upon. Otherwise,
it's too easy for them to take the bad practices of some as example.

If someone wants to punish the original poster, then it can all
be done simply by reporting him. The point of making it public
is to try to limit further practice by others, and I don't think
the removal of the original subject from the reply helps
this process.

He's also be in a far better position when he's announcing
spam if he included a link to Mark Zenier's guide to the hierarchy,
ftp://ftp.eskimo.com/u/m/mzenier/seguide9706.txt
because that well explains where ads are supposed to go.

Michael

Good thoughts, thanks.

But S.E.D should be S.E.D.P.HP, where P= Politics, and HP= Horse Puckey.

Don
 
E

Eeyore

Jan 1, 1970
0
Don said:
Good thoughts, thanks.

But S.E.D should be S.E.D.P.HP, where P= Politics, and HP= Horse Puckey.

What's horse puckey ?

Graham
 
D

Don Bowey

Jan 1, 1970
0
What's horse puckey ?

Graham

To get all the valuable nuances of the term, you should watch some of the
"MASH" TV series. It appears to be an old military expression.
 
J

JeffM

Jan 1, 1970
0
The point of making it public is to try to limit further practice by others
Michael Black
Yup.

and I don't think the removal of the original subject from the reply
helps this process.
Valid point. My thinking that everyone views in a threaded manner
is a dangerous assumption.
I guess there are also some newsreaders
that don't keep threads together when the Subject line changes.
(The original Google Groups was notorious for that.)
 
E

Eeyore

Jan 1, 1970
0
Don said:
To get all the valuable nuances of the term, you should watch some of the
"MASH" TV series. It appears to be an old military expression.

I've seen quite a number of those but don't recall the term.

Over here we do however sometimes talk about ppl talking 'horse manure' - similar
?

Graham
 
D

Don Bowey

Jan 1, 1970
0
I've seen quite a number of those but don't recall the term.

Over here we do however sometimes talk about ppl talking 'horse manure' -
similar
?

Graham
Yes, that's it.

Don
 
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