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From: firstname.lastname@example.org (LuuneeToon)
Subject: Re: Please help with PIC processor circuit.
Date: 14 Oct 2002 21:10:55 -0700
References: <email@example.com> <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org>
NNTP-Posting-Date: 15 Oct 2002 04:10:55 GMT
Rich Webb wrote in message news:...
> On 8 Oct 2002 08:56:12 -0700, email@example.com (LuuneeToon) wrote:
> >Rich Webb wrote in message news:...
> >> On 4 Oct 2002 21:36:10 -0700, firstname.lastname@example.org (LuuneeToon) wrote:
> >> >It needs to be able to, using a photoelectric sensor, calculate wheel
> >> >RPM. I will be using a C compiler for floating point math.
> >> Is this for the control circuit to a 250 tph ball mill or for a
> >> breadboarded homework project? If it's homework, the concept is to learn
> >> by doing. Have you tried something that isn't quite working and need
> >> some additional insight or just looking for a cookie cutter solution?
> >Not sure what a 250 tph ball mill is. Probably something not related
> >to my question. This isn't a breadboarded homework project for school.
> It's a 250 ton per hour rock crusher. Needs a bit more robustness and
> reliability than, say, a home-made anemometer. ;-)
> >It's my own personal project, doing it on my free/spare time. However,
> >I havn't been able to get anywhere. That's why I've posted this asking
> >for help. If this circuit is relatively simple and someone can send it
> >to me or post it up, or if you know of a website that will really help
> >me get started, please post or e-mail me at LuuneeToon@yahoo.com
> The most straightforward way may be to have the sensor triggered by a
> patch of contrasting brightness on the rotating shaft. When it goes high
> (or low) capture the counts in a free-running clock. WRT using
> interrupts versus polling, each has advantages and disadvantages. You
> may want to try them both. The number of counts between pulses is
> linearly related to rotation rate.
> How you get the pulse depends on what kind of photoelectric sensor you
> have. Could be as simple as biasing it and wiring it to the input of a
> TTL buffer. Probably better to use a simple op amp voltage comparator
So how would I go about doing that? Is there a circuit available on
the web with the components that I need or do you have a circuit of it
already? Is it simple? Please help.
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