FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   PreferencesPreferences   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Forum index » Electronix » components
newbie question
Post new topic   Reply to topic Page 1 of 1 [10 Posts] View previous topic :: View next topic
Author Message
Lostgallifreyan
electronics forum Guru Wannabe


Joined: 13 Apr 2006
Posts: 241

PostPosted: Fri Jul 21, 2006 2:16 pm    Post subject: Re: newbie question Reply with quote

William P.N. Smith <news2006c@compusmiths.com> wrote in
news:hll1c2dfbkpirhab0aq3o7smddjstmljbj@4ax.com:

Quote:
Lostgallifreyan <no-one@nowhere.net> wrote:
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*)


Yep Smile 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.
Back to top
William P.N. Smith
electronics forum addict


Joined: 02 Nov 2005
Posts: 80

PostPosted: Fri Jul 21, 2006 1:29 pm    Post subject: Re: newbie question Reply with quote

Lostgallifreyan <no-one@nowhere.net> wrote:
Quote:
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*)
Back to top
Lostgallifreyan
electronics forum Guru Wannabe


Joined: 13 Apr 2006
Posts: 241

PostPosted: Fri Jul 21, 2006 12:22 pm    Post subject: Re: newbie question Reply with quote

"voodoochile" <voodoochile3@blueyonder.co.uk> wrote in
news:PA2wg.100$4a.18@fe2.news.blueyonder.co.uk:

Quote:
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.
Back to top
Eeyore
electronics forum Guru


Joined: 22 Jun 2006
Posts: 642

PostPosted: Fri Jul 21, 2006 11:32 am    Post subject: Re: DON'T MULTI-POST Reply with quote

"William P.N. Smith" wrote:

Quote:
"JeffM" <jeffm_@email.com> wrote:
voodoochile MULTI-POSTED:

Hey, didn't you just say that in some other newsgroup?

Yes - he went and multi-posted his msg.

Ironic really.

Graham
Back to top
William P.N. Smith
electronics forum addict


Joined: 02 Nov 2005
Posts: 80

PostPosted: Fri Jul 21, 2006 11:17 am    Post subject: Re: DON'T MULTI-POST Reply with quote

"JeffM" <jeffm_@email.com> wrote:
Quote:
voodoochile MULTI-POSTED:

Hey, didn't you just say that in some other newsgroup?
Back to top
William P.N. Smith
electronics forum addict


Joined: 02 Nov 2005
Posts: 80

PostPosted: Fri Jul 21, 2006 11:16 am    Post subject: Re: newbie question Reply with quote

"voodoochile" <voodoochile3@blueyonder.co.uk> wrote:
Quote:
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.
Back to top
voodoochile
electronics forum beginner


Joined: 21 Jul 2006
Posts: 5

PostPosted: Fri Jul 21, 2006 11:08 am    Post subject: Re: newbie question Reply with quote

Thanks for the support.

Yes the device is okay with line of sight.
..
"Lostgallifreyan" <no-one@nowhere.net> wrote in message
news:Xns9807552357EFBzoodlewurdle@140.99.99.130...
Quote:
"voodoochile" <voodoochile3@blueyonder.co.uk> wrote in
news:LaZvg.2076$I9.1108@fe2.news.blueyonder.co.uk:

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.
Back to top
Lostgallifreyan
electronics forum Guru Wannabe


Joined: 13 Apr 2006
Posts: 241

PostPosted: Fri Jul 21, 2006 7:22 am    Post subject: Re: newbie question Reply with quote

"voodoochile" <voodoochile3@blueyonder.co.uk> wrote in
news:LaZvg.2076$I9.1108@fe2.news.blueyonder.co.uk:

Quote:
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.
Back to top
JeffM
electronics forum Guru


Joined: 02 May 2005
Posts: 1007

PostPosted: Fri Jul 21, 2006 5:23 am    Post subject: DON'T MULTI-POST Reply with quote

was: newbie question

voodoochile MULTI-POSTED:
http://groups.google.com/groups/search?filter=0&enc_author=-8aS1h0AAACC4qYC26JWcDY7vUtk0iWv-P3beutfjv_gfOY8KsInLw&scoring=d

Quote:
I wonder if anyone can help me with this simple problem

http://groups.google.com/group/sci.electronics.basics/browse_frm/thread/7b7c0624331012bb/3958f18673b5f374?q=EVERY-group-*-*-*-*-*-*-*-*-appear+*-proper-answer-*-*-*-given+much-easier-*-*-*-*-what's-going-on+*-frowned-on+*-correcting+*-polite-*-mention-*-*-*-*-*-*-*+Just-because-*-*-*-*-*-*-*-*-does-not-mean-*-*-*-*-*-*+*-Followup-To-*+*-*-*-too-lazy-*-*-*-*-*-appropriate-*+*-*-_perfect_-*-*-*-*+*-*-*-*-two-groups-*-*-aren't-*-different
Back to top
voodoochile
electronics forum beginner


Joined: 21 Jul 2006
Posts: 5

PostPosted: Fri Jul 21, 2006 4:59 am    Post subject: newbie question Reply with quote

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.
Back to top
Google

Back to top
Display posts from previous:   
Post new topic   Reply to topic Page 1 of 1 [10 Posts] View previous topic :: View next topic
The time now is Thu Aug 24, 2017 10:28 am | All times are GMT
Forum index » Electronix » components
Jump to:  

Similar Topics
Topic Author Forum Replies Last Post
No new posts Timex crystal question Marvelheroes Repair 0 Wed Aug 09, 2006 8:43 pm
No new posts Another question voodoochile components 0 Fri Jul 21, 2006 1:52 pm
No new posts Current sense and diff. amp question Johnny design 3 Fri Jul 21, 2006 8:53 am
No new posts question about solartron carrie_yao@hotmail.com design 0 Fri Jul 21, 2006 7:02 am
No new posts newbie question voodoochile Misc 1 Fri Jul 21, 2006 5:00 am

Copyright © 2004-2005 DeniX Solutions SRL
Other DeniX Solutions sites: Unix/Linux blog |  Unix/Linux documentation |  Unix/Linux forums |  Medicine forum |  Science forum  |  Send and track newsletters


Powered by phpBB © 2001, 2005 phpBB Group