voltage warning light

Archiver

Hello

This isn't directly related to the stamp, but you guys are the smartest
group of guys I know.

I'm trying to make a stampless circuit that will turn on a LED (or light)
when the source voltage drops below 13 volts (this is for an automotive
project, if you couldn't tell already [noparse];)[/noparse]

Thanks in advance!
Ben

Archiver

At 02:16 27.05.2001 -0500, you wrote:
>Hello
>
>This isn't directly related to the stamp, but you guys are the smartest
>group of guys I know.
>
>I'm trying to make a stampless circuit that will turn on a LED (or light)
>when the source voltage drops below 13 volts (this is for an automotive
>project, if you couldn't tell already [noparse];)[/noparse]
>
>Thanks in advance!
>Ben

Ben,
you are correct, no needed BASIC Stamp for this task.
With attached file (7.6kB) you see one solution in a basically scheme of
design:
OPV LM711, comparating a part of cars voltage (R-divider) with a
reference 2.5 Volt, given by AD580. Both ICs without much money.
Comparators with included voltage reference see to Burr-Brown and others.
With some more soldering
you have a simple solution also with two transitors, a zener-diode with about
6 Volts and some resists. Regards Klaus Zahnert