Re: Automatic Pellet Dispenser

[Marc_F_Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On 23 Feb 2007 05:45:56 -0800, "Dave Harper" <dharper@xxxxxxxxxxxxxxxx> wrote
in message  <1172238355.967425.64000@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

>For what it's worth, I had pretty much the same reaction as "jack ak"
>when I read the initial post.  Having read the details in the followup
>post it's obvious that it's an entirely different situation.  I love
>dogs and am impressed with your rescue efforts; I don't think I could
>do it myself - I'd find it too depressing.
>
>That said, perhaps you could provide some more details.  It's been a
>number of years since I last had a dog and I'm not familiar with
>kibbles.  Therefore:
>
>1) Could you describe kibbles?  Approximate size, weight, shape, etc.
>Anything that might be relevant information to consider when
>constructing a dispenser.
>
>2) Are you thinking in terms of a single unit that would dispense to
>all crates or something you would replicate on a crate by crate basis?
>
>3) Do you have any problems preloading the dispenser with individual
>kibbles or are you looking for something with a hopper type
>arrangement where you just pour in a bag of kibbles and somehow the
>kibbles settle out into individual treats before being dispensed?
>

Same questions here. (My wife designed and built such a feeder when working
in a neuroanatomy lab almost 40 years ago. She quickly learn that some one
else beat her by a few decades ...  Have you looked for a commercial version
or searched for existing designs?)

If the pellets are all lined up vertically nice-like, all you need is a hole
(slightly larger than the diameter of one pellet) drilled  through a traveler
slightly thicker than one pellet and to cause the traveler to  slide from
side to side. A solenoid can be used to pull the traveler forward  so that a
pellet can enter the hole (but not pass through). When the solenoid is
released, the traveler moves back to its original position owing to a spring
(or second solenoid) and the pellets drops out through a hole in the rack
holding the traveler.

                        O
                        O
At Rest:   ____________|O|___
           | |---------------
           | |_______________

                        O
Loading::  ____________|O|____
           ------------|O|----
           | |_______________

                       O
Delivering:___________|O|____
           | |----------------
           |O|_______________

                      O
Delivered !__________|O|___
           | |-------------
           | |_____________
            O


Similar thing can be done with a rotary motion using a stopcock like device
in which the hole for the pellet only goes half-way through the stop cock.
You can move with either a rotary solenoid or a stepping motor (doesn't need
to reverse).

HTH ... Marc
Marc_F_Hult
www.ECOntrol.org