Re: Bad Idea: Put 9V Flasher LED on top of 9V Battery??

From: NoMailPlease (DoNotSendMe_at_AnyMail.OK)
Date: 06/19/04 

Date: Sat, 19 Jun 2004 02:15:06 GMT

That sounds alot safer. I tried using 2 AA batteries to power the flasher
LED and it works fine. I'm very interested to see how long the AAs work vs.
the 9V..

I also ran across a flashing circuit that's supposed to last a year at
http://www.discovercircuits.com/L/lite-flash.htm. If I keep going through
batteries or don't get brave enough to attach to the car battery, I might
just build it and see how it performs.

"Robert C Monsen" <rcsurname@comcast.net> wrote in message
news:P%MAc.71286$HG.63775@attbi_s53...
>
> "NoMailPlease" <DoNotSendMe@AnyMail.OK> wrote in message
> news:N3MAc.768306$Pk3.569221@pd7tw1no...
> > I've always had a car alarm and in my new car I figured I'd save the
> $300
> > and just put a flashing LED on the dashboard. There was a blank
> knock-out
> > panel on the dash, so I bought a flashing LED and mounting grommet.
> I fed
> > the battery connector to the coin box and this is where I plug the
> LED into
> > a 9V battery.
> >
> > The whole thing works great for at least 5 days until the battery
> dies. (I
> > leave it flashing 24 hours per day.) I've seen articles about
> attaching
> > flashing LEDs to the car battery, but given my tiny knowledge of
> > electronics, I'd rather keep this circuit separate.
> >
> > My dream now, is to build a better circuit that would allow the
> flasher to
> > live for several weeks. I never knew that 9V batteries had such
> short
> > lives. If I were to create the most efficient LED flasher circuit
> possible,
> > would it be worth the trouble. Or, would I gain just a few more
> hours out
> > of the whole thing?
> >
> > If it's worth the trouble, do you know of any plans to build a
> flashing LED
> > that runs on AA's, etc??
> >
> > Thanks for all your help!
> >
>
> You may want to consider tying into your car battery. You can get
> cigarette lighter adapters, which will give you 12V. Use that to power
> a 7809 voltage regulator (which you can get anywhere electronics parts
> are sold, like Radio Shack, for example.) Use the output of the 7809
> to power your flasher.
>
> Your flasher will probably work with 12V with a 150 ohm resistor in
> series; it's probably worth a try.
>
> The other possibility is rechargable batteries.
>
> Regards
> Bob Monsen
>
>

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