[nzlug] Embeded problem - Dairy

[Michael Adams]

On Sun, 30 Dec 2007 19:12:19 +0900 (JST)
Andrew Errington wrote:

> >
> > The biggest cost i would have thought is automating the gate. Cows
> > are BIG really BIG, and strong. If he doesn't already have a
> > reliable electro-mechanical gate (ie one you can push a button and
> > it opens/closes etc) then there is a bit of cost in an
> > electro-mechanical system to do it reliably in that dirty, wet
> > environment populated by big animals.
> >
> 
> True, but most suggestions made here have assumed that the gate
> mechanism is separate, and that the 'cow detector' has a simple output
> that opens or closes the gate.  It is also true that each design has
> its benefits and potential problems.  An engineer's job is to design a
> system that works with an acceptable performance within the given
> constraints.
> 
> A solution to the gate problem might be to have the 'cow detector'
> flash a light and sound a horn when the cow walks past, then an
> assistant could operate the gate at the right time, leaving the
> dairyman to concentrate on the dairying.

* Except there is often only one man in the shed;

> 
> Generally for this kind of problem you design a strong gate and
> fixture and have a lightweight actuator that won't be damaged if it is
> jammed or forced.  For example, a motorised arm that connected by a
> spring to the gate.  If the gate is free to move then the motor will
> move the gate to the desired position, but if the gate is not free to
> move then motor will compress or stretch the spring rather than
> destroy itself.
> 
> Andrew
> 

Perhaps the OP is discussing this with some (the dairy farmer?) off list
or perhaps on leave but until he gets back on this thread it looks like
we have enough options for him to consider. Else we are floating fairies
around (general comment not aimed at you specifically Andrew).

-- 
Michael

All shall be well, and all shall be well, and all manner of things shall
be well

 - Julian of Norwich 1342 - 1416