On Tue, Jun 15, 2004 at 12:49:22AM +0300, Arne Ansper wrote:
| I crashed my plane do to insufficiently charged battery and decided to
| build low battery alarm. I looked around and there seem to be two kind of
| alarms: with LEDs and with buzzer (and some of them have both).
|
| What kind do you preffer? I found very simple and cheap schematics
| http://www.ncws.com/rcrock/lowbat3.htm that uses buzzer.
Personally, I use these in most of my planes --
http://www2.towerhobbies.com/cgi-bin/wti0001p?I=LXSZ87P=7
... so I guess I'd have to say I prefer buzzers. It weighs 10 grams,
but if you're worried about the weight I'll bet it wouldn't be too
hard to shave half of that off by cutting off bits of plastic and
plugs that you don't need.
Mostly I use these for the lost plane locater feature -- I typically
fly near trees, and it's amazing how hard a plane can be to find if it
lands in a tree -- but the dead battery alarm has saved me some grief
as well. It's also useful to know when you bump a plane in your car
and accidently turn it on (it beeps.)
Of course you could roll your own, but at $15 I wonder if it's cost
effective ...
Still, your little circuit looks intriguing. Two grams looks hard to
beat, and it looks like it's a little cheaper too.
Back to buzzer vs LED -- wouldn't an LED be hard to see in the air,
with the bright sun to deal with? You can't hear the buzzers at more
than 100 feet or so, but I wonder if you'd be able to see a LED at 20
feet in the sun.
--
Doug McLaren, [EMAIL PROTECTED]
`Adding sound to movies would be like putting lipstick on the Venus de Milo.'
-- actress Mary Pickford, 1925
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