# Really easy wall wart question



## paulcav151 (Nov 15, 2009)

I am embarressed to have to put this out here, as I thought it couldn't be any simpler... I have one of those crawling hands that vibrates. I plan to put it in a spider victim. It runs on 2 C batteries, and the switch goes up for forward, down for backward, and off in the center. I have two 3vdc wall warts, one 100ma, and a 500ma. Only two wires to connect, and neither seems to work with the wires connected in either direction. I did verify with a meter that the wall warts are putting out power. What am I missing?


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## DarkLore (Jan 25, 2009)

You don't specify where you connected the adapter wires. 

If there were two batteries, then I would presume they sit next to each other in the crawling hand, with one flipped. Have you checked to make sure your connections are at the start and end of the battery sequence (pos, neg)? Which means the negative side of the adapter on the spring connection for the battery and the other on the flat spot the batteries connect to?


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## fritz42_male (May 5, 2009)

And the obvious thing - make sure the wall warts are putting out DC not AC!


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## paulcav151 (Nov 15, 2009)

DarkLore said:


> You don't specify where you connected the adapter wires.
> 
> If there were two batteries, then I would presume they sit next to each other in the crawling hand, with one flipped. Have you checked to make sure your connections are at the start and end of the battery sequence (pos, neg)? Which means the negative side of the adapter on the spring connection for the battery and the other on the flat spot the batteries connect to?


The batteries were stacked head to toe. I cut the battery holder off and connected wire to wire. I didn't want to take the holder with the switch apart in case I needed to reattach it, like I did cuz I couldn't get it to work.

It is definately DC


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## hedg12 (Jul 6, 2008)

Any chance you can take some pictures?


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## paulcav151 (Nov 15, 2009)

hedg: Pictures here
http://photos.myhallowistmas.com/GalleryThumbnails.aspx?gallery=331113


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## hedg12 (Jul 6, 2008)

My only guess is that your warts don't have the oomph (that's the technical term) to power the hand. The motor could potentially draw a considerable amount of current to run. That would explain why they use C cells - AA's would run down too fast. It shouldn't matter which wire is positive and which is negative - the motor should run either direction. 

That's my best guess, anyway.


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## scarymovie (Feb 14, 2010)

Did you fix this yet?


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## paulcav151 (Nov 15, 2009)

No...


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## bourno (Jan 21, 2006)

Did you happen to have the meter on the terminals while off and then the device on? Am guessing that Hedg could be correct. If the device needs more juice, the voltage will drop down way below 3 volts. Would have thought the hand may still run, but just very slowly.



hedg12 said:


> My only guess is that your warts don't have the oomph (that's the technical term) to power the hand. The motor could potentially draw a considerable amount of current to run. That would explain why they use C cells - AA's would run down too fast. It shouldn't matter which wire is positive and which is negative - the motor should run either direction.
> 
> That's my best guess, anyway.


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## corey872 (Jan 10, 2010)

Turning on the switch? (That would be my luck.) I doubt your 100ma supply has the 'juice' The 500ma might be closer. If you have a meter which measures amps you could put it in series with your batteries and measure the current draw of the hand. ie:

A-----[meter]-----[batts]----[hand]----B, then connect A to B and turn the hand on.

Alternately, if you can only measure volts, you could hook up the 500ma supply and measure the voltage. If the voltage drops down near or below 2V, that's in the range of 'dead' batteries, so the hand probably won't work.

Lastly, batteries are a pure DC source. Most wall warts - even if they claim 'DC' are really only roughly rectified AC, so the 3V/500ma rating may be at peak power and the average would fall below that.


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