Flapping "For Sale" sign, need design help for

Windshield wiper motor.

John

Exactly.

12VDC GEARHEAD MOTOR (for 2001 Saturn L-Seies automobiles) CAT# DCM-171 $ 15.95 USD each

Good luck Chris

to

and

can't

DC

time.

Self rotating signs were once popular. Theyre signs in the shape of a vertical rotor, and turn round in the wind. Easier to make than the tronic version.

shape of sign, birds eye view:

( )

Putting a bunch of tronics motors and batteries on the street would ensure it gets nicked, in many places.

NT

Look into large r/c type servos for sailboats.

--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm

Duhhhh! Windshield wiper motor: ashamed of myself for not thinking of that :) Can I run that off a battery smaller than a car battery? (Just ocurred to me that if I have a car battery sitting out there I'm inviting theft. But if I can run it from a smaller battery of some type, it would both be fairly unattractive as an item of theft, *and* I could conceal it more readily than a car-sized battery (out of sight, out of mind). [The Gearhead motor: high speed is ...12 Vdc, 4 Amps. Low speed ....12 Vdc, 0.91 Amps.]

((Am also looking at the sailboat servo idea, but the WWMtr. idea looks pretty attractive, esp. if I can cut down on the power supply size.))

Not yelling; caps only for emphasis ----> THANK YOU FOR THE RAPID RESPONSES !

Christopher A. Steele

Rent or buy one of those inflatable men, that flap around in the wind. They attract lots of attention.

--
Regards,
   Robert Monsen

"Your Highness, I have no need of this hypothesis."
     - Pierre Laplace (1749-1827), to Napoleon,
        on why his works on celestial mechanics make no mention of God.

Yes. You could run it off flashlight batteries if you wanted to, but you'd have to buy a lot of flashlight batteries. If you run it on low speed (0.91 A at 12 V) for 8 hours, it will take about 7.3 amp-hours of battery. A 12 V sealed lead-acid "gel cell" battery rated at 9.0 amp-hours or more will weigh around 5 pounds and do the job. The GC-1214 for $25 at the same place with the wiper motor is a 12 V, 12 amp-hour battery and will work fine.

You have to buy a battery rated more than 7.3 amp-hours, since the rating assumes that you'll use the battery up over 20 hours. Since you'll use it up faster than that, you don't get the full rating.

When the battery is discharged, you can charge it back up with a normal

12 V car battery charger. Set it to the lowest current rating you have; a 2 amp or less charge rate would be best. This is not the right way to charge a gel-cell if your life depends on it, but for twirling a sign it will work fine. You need to put a bit more than 7.3 amp-hours back in, so if you have a 1 amp charger, you need to charge for 8 or 9 hours; a 2 amp charger needs 4 or 5 hours, etc.

Since the current is pretty low, you can put the battery some distance from the sign where it's out of the way (like, behind a tree, or in the water meter hole) and run a 16 gauge or so extension cord to the sign. Even if you put the battery right at the sign, a 5 amp or so fuse in the battery positive lead is a good idea.

If you have a cheap battery charger rated at 1 amp or more, you can even skip the gel-cell battery. Put the battery charger in the garage and run an extension cord from the 12 V clips on the battery charger to the sign. Put a lamp timer on the 120 V plug of the battery charger and you don't even have to remember to turn it on. If you have a fancy battery charger, this won't work, as it wants to see some voltage on the leads to verify that it's really hooked up to a battery.

If you don't have any battery charger but you still want to skip the battery, buy a DCTX-1212 wall transfomer for $4.50 at the same place as the wiper motor. Plug it in in the garage, run an extension cord on the

12 V side to the wiper motor, done.

Matt Roberds

I think it's a bad idea. It shows signs of a desperate seller. Subtlety works better. I think a 4 ft wide sign won't be too hard to miss. :)

Cheers