need help building dog feeder - looking for auger to dispense food

I need some assistance in my latest endeavor to build a programmable automatic dog feeder. The primary reason for this is the cost of the
ones I have found in stores and online, and that they are to small. Programmable timers are easy to come by and quite cheap. The harder part to come by is the auger device to dispense the food. Does anyone know of any source for this type thing? Ideally I would for the stepper motor to be attached via relays, powered by low-voltage and have a 9-12volt transformer attached with keeps the nicad batteries mantained at all times, however should the power go out the unit will continue to function off battery power. Any suggestions?
TIA,
Inet
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The only commercial devices I can think of that contain an auger are the meat mincing attachments you can get for some kitchen food mixers (the famous Kenwood Chef definitely has one)- perhaps if you made a replacement grille for the end of the mincer with much larger holes so the dog food comes out in chunks without actually getting minced, it would work? it might need rather more torque than you can get from a stepper motor, though - I'd use a nice beefy DC motor for this job. I find you can get an impressive amount of "oomph" out of windscreen wiper motors, which are dirt cheap from a breakers or junkyard (I picked up a couple of Ford Fiesta ones, a favourite among experimenters, for five pounds each), and they run on 12V and are of course designed to be low-maintennance. Just a couple of ideas.
Hope this helps
Tom
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I have the perfect Auger for you -
It's bulb planting season, and Home Depot has these little augers that you throw in your cordless drill - They'd be perfect size for dog kibble - about 2.5" in diameter with like a 5/16 to 3/8 shaft and maybe 18 inches long. You could find a PVC pipe to fit them in to I'm sure. http://store.yahoo.com/electricfence/too-2029.html
Those guys sell similar looking ones, but they're amazingly stupid expensive from that site.
Andy

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I like that idea... I had already checked out drillbits, but they were in the neighborhood of $40 each. I'm still looking for some off the wall site who carries things for hobbists/prototypers like gearboxes, wheels, and misc plastic parts....Hoping one will turn up soon.
Thanks for the ideas all!
-Inet
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I think Andy's auger idea will work great. Also, Tom is right about the motor. I wouldn't use a stepper motor for this application. Not enough torque and complex to control. Just use a DC gearmotor driven with a relay on a timer. www.robotzone.com has a good selection.
Now for the batteries. If you're going to buy batteries, buy NiMH instead of NiCd. For a similar price, you get alot more capacity and greater longevity. Charge the batteries with a simple constant-current charger based on the LM317. Trickle charge them at a current no greater than C/10 (e.g. - if you use 1800 mAH batteries, charge them at 180 mA or less).
BRW
On 7 Sep 2004 01:45:59 -0700, snipped-for-privacy@hotmail.com (Inetquestion) wrote:

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My girlfriend's commercially bought automatic cat feeder used something like a revolver arrangement like a revolving pistol. Each chamber held food and when the timer timed out a new chamber was opened. It used a battery for the timer and a wind up spring to turn the chamber cover.
Charles L.
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Wow. I didn't think any of us robotics guys could get a girlfriend.
BRW

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<Bennet Williams> wrote in message

Sure we can, but they take a while to build...
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Charles Prevatte wrote: ...

...
An alternative to the auger that would work similar to this would be to have a large(ish) wheel with holes drilled through it. It would be thicker than the kibble and the holes would be wider than several kibble widths. Place the wheel horizontally under the hopper so that when it rotates some kibble drops into the holes, is moved out from under the hopper and on the other side, falls into a dish.
Something like the elevating wheel on this page. http://www.sentex.net/~mwandel/marbles/machine2.html
The following look suspiciously like what the OP was asking for.
http://www.fancypaws.com/aufe.html http://www.uniquedistributors.com/elpetfeed.html http://www.petcarecentral.com/larautpetfee.html?AID 308425&PIDR7975
Anthony
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Find an old fidge with an in the door ice despenser, most have some type of auger in the ice bucket..
Thanks

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Brilliant! What a simple solution!
From:danscott snipped-for-privacy@you.com

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Awesome idea! I'll check on that tomorrow morning
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