[ATM] Slurry/water dispenser

[Jerry]

I somewhat agree with Michael. The difference being that I think it best to
be there and tend to those things in person, and turn the machine off if you
must leave it.  I imagine that commercial shops can't give 100% attention
100% of the time. But they are probably more able to absorb the loss when
something occasionally goes wrong and breaks something. Even if I automated
the slurry feed, I would still be there paying attention.

But I understand the urge to be able to leave the machine running unattended
for short periods of time. 

If you are adept at programming it, I would say use a PIC rather than a 555
timer. It's more flexible. It would be easy to add features or change the
purpose entirely should you think of some that would be useful.

One thought that occurs to me is that in the end, dispensing slurry is a
mechanical operation and you already have timing in the machine. If you were
adding slurry or water, the stroke of the machine is timed and the location
of the application of slurry can be timed to miss the back of the tool by
having the stroke of the arm pump the slurry, spray water, or open a valve
at a specific part of the stroke. No need for any electronics.

Jerry


 
-----Original Message-----
From: Julio Sanchez
 
I am still in doubt whether to use the 555 or a simple PIC such as the
16F84. I am loose with PIC circuits and programming (I even wrote a book
about it) but not so with PIC-less circuits. Then, with a PIC it would be
easy to drive a 7-segment LEDs (or even a LCD). This assuming that the
system should provide some info and feedback to the user.
Is this getting too fancy?
Regards,
Julio



-----Original Message-----
From: atm-bounces at atmlist.net [mailto:atm-bounces at atmlist.net] On Behalf Of
Michael Lindner
Sent: Sunday, February 04, 2007 11:41 AM
To: Julio Sanchez
Cc: atm at atmlist.net
Subject: Re: [ATM] Slurry/water dispenser

Julio Sanchez wrote:
> I have enyoyed and learned from all the feedback on the AC controller
circuit for a water or slurry dispenser. I don't want to industrialize
amateur telescope building. My problem is that I have a home-made
grinding/polishing machine (like many of you guys) and sometimes I forget to
add the few drops of water or polishing solution every few minutes. Perhaps
I got distracted with my computer or with a minor family crisis . Then the
polisher sticks to the glass and I have a big problem in my hands. I have
chipped more than one blank and tore more than one good pitch lap on such
occasions.
> So it would nice to have a system that puts in the water or slurry for me
if I forget to do it, and then I can go and log-on without having an
explosion in the back of my mind.
> That is my motivation in this project. Whatever comes out I will share
with all of you, of course.

Thanks Julio,

In that spirit, here's what I do for my homemade grinding machine. For 
grit, I don't do anything - I stand there. There are too many variables, 
and automating the problem is to me more work than standing there. 
Likewise for figuring.

For polishing, I have two mechanisms I use. First, an IV bag (or even a 
ziploc, see my earlier posts) drips water on the work, one drop every 
few seconds (the nice thing about the IV bag is you can adjust the flow 
for changes in humidity, size of the work, etc - with the ziploc you can 
increase the flow by making the hole bigger, or replace the bag if it's 
too big). It doesn't matter if the drops hit the back of the tool, it 
will eventually drip down onto the blank. That gives my about 15 minutes 
between having to do anything with the machine. My second piece of 
equipment is a watch with a count down time. Every 15 minutes it beeps 
and wherever I am I know it's time to check the machine and add CeO or 
whatever.

Clear skies.
-- 
Michael Lindner
http://www.starastronomy.org *** http://home.att.net/~mikel
http://www.atmsite.org *** http://www.atmlist.net
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