Re: Circuit Designs

Hi guys,

I much appreciate the time and help you're giving me with this.

The motor will be controlled by a PIC chip embedded in the circuit. The
motor will have to rotate in order to pull a spring loaded hatch back. The
volume of feed released will be calculated from dimensions of the hole and
so when the required feed (set by a rotary dial switch on the front of the
unit) has been expelled the motor will reverse (transistor, DPDT relay+PIC
chip?) thus closing the hatch. The rest of the journey for the food is down
to gravity.

Bearing in mind that these circuit designs will be preliminary - my teacher
will check and refine them so no need to worry about mistakes. I just need a
general idea of what the circuit should contain.

I agree with Jerry about the feedback system - possibly a pressure sensor on
the transporting tray or an infra-red sensor by the hatch.

I hope this provides enough info - please ask if more is needed.

Many thanks again,

James

>>
>> Even more specifics are required. What kind of relationship do you need
>> between the input and the output? What kind of signal does the motor
>> need to see? How does the motor need to move? What is the mechanism of
>> the feeding? Is it a cam that's pushing out food at intervals, or is it
>> some sort of screw drive?
>>
>> Be very specific about the type of signals you need to provide. Do you
>> need a pulse for each feeding interval that gets wider as you require
>> more food? Frankly, it sounds like you don't really know what the
>> input/output relationships need to be, and its very hard to design a
>> circuit when you don't know EXACTLY what you need it to do. You'd be
>> much better off designing the feeding mechanism and testing it with a
>> function generator before you try to build a circuit to drive it.
>
> Scott is right on. If my newsreader had shown his first response, I
> wouldn't have joined the thread. I might suggest a design and pitfalls of
> the design of a mechanical feeder, but that's another thread. One point is
> worth while now, though. The design should make it possible to determine
> that food was actually dispensed. It would be most unfortunate for the
> machine go through its motions with the hopper is clogged and no one the
> wiser.
>
> Jerry
> --
> Engineering is the art of making what you want from things you can get.
> ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯


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