Re: Simple LED Alarm Bell for CCTV recorder

["Jackcsg" <nospam@xxxxxxxxxx>]

You can buy them with the resistors embedded, at 5 to 28vdc, some even to 60
vdc. (I'm looking through my Newark Catalog), they draw 17 ma at 12 vdc. I
know the Shack carries them...lord knows I've bought a few hundred
there....(I love it when they ask me "what's it for?")

"Crash Gordon®" <NONE@xxxxxxxx> wrote in message
news:rdrZd.46$cp.1735@xxxxxxxxxxxxxxxxxx
You'll have to knock the voltage down for the LEDs too..otherwise they make
a nice crackly-popping sound as the plastic shoots across the room.

I "think" from 12v to 3v is a 660 ohm resistor...to give you voltage
drop...something like that.


<me@xxxxxxxxxxx> wrote in message
news:lr9c31t6t1qgvqiijck5m2v8fmslnst55b@xxxxxxxxxx
> On Mon, 14 Mar 2005 17:35:52 -0500, "Jackcsg" <nospam@xxxxxxxxxx>
> wrote:
>
> >It was simple until you said you wanted the LED to flash. Are you good
with
> >a solder gun? It is easily done, but it's going to be a little intricate
if
> >you're only a DIY'er. Do you want the buzzer to be intermittent with the
> >LED, or a small steady buzz? The switches are easy because you can use a
> >DPDT switch to "shunt" the alarm device.
>
> I think a small steady buzz.
> Note that the CCTV DVR box has 8 wires all 500ma, 12volts each.
> All 8 wires from CCTV DVR would go into one black box that is drilled
> on the front, 8 LEDs, 8 switches (1 per sensor), and buzzer inside.
>
> There should be some way to handle the amp and voltage so it doesn't
> go back and blow up the CCTV box.
>
> I've forgotten everything they taught me in science classes. If I had
> a diagram I could show it to the people in Maplin.
>