[AT] Re: AT Digest, Vol 12, Issue 16

[Chris Britton]

I wish I would have seen the message.  I made up a 'lights on' buzzer for my
ford N's a while back.  Unit used simply relay 'logic'.  It had a current
draw of about 50ma while the tractor was running, and no current draw when
the tractor was off.  Unit would buzz if you left the headlamps on when you
killed the ignition switch.

I made a few other projects based on variations of that design.. low oil
pressure buzzers.. battery discharge indicators.. etc. And a simple latching
circuit that was good for running an unattended engine.. like one where you
have a tractor running a pto genset or water pump.  If the engine stalled
( lack of fuel) power to the points was shut off so the points didn't
burn/discharge the battery.  Circuit could also be modified to do auto
shutoff on low oil pressure with just a few changes.  Pretty much all using
low current, low voltage 'relay' logic.

For tractors with generators, there were even more small projects to do, as
you had a very good 'engine is running' reference point via the armature
voltage which was isolated from the battery via the cutout relay/vr.
Like yours.. mine fit in a project enclosure box the size of a deck of
cards.. however would have fit in one half that size.

Soundguy

>From: "Spencer Yost" <yostsw at atis.net>
>Subject: [AT] Idiot Alarm
>About 4 months ago, I asked for some help from the electronic gurus on this
>list for a small circuit board I was building.  It was for an idiot alarm
>for the headlights on a vehicle that didn't have one.  After all the help