Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!dali.cs.montana.edu!milton!whit
From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: EVENT COUNTER
Keywords: counters,data aquisition
Message-ID: <6992@milton.u.washington.edu>
Date: 2 Sep 90 04:53:23 GMT
References: <26dd5749-39csci.electronics@vpnet.chi.il.us> <26de96e2-39c.1sci.el <26ded58a-39c.2sci.electronics-1@vpnet.chi.il.us>
Organization: University of Washington, Seattle
Lines: 21

In article <26ded58a-39c.2sci.electronics-1@vpnet.chi.il.us> akcs.rick@vpnet.chi.il.us (fred salchli) writes:
>More info about my problem . . . . . . .  .
>      I'm attempting to build a BIG system, 144 or more channels and
>building optical sensors would involve rewiring our facilities, and
>refitting all our cages. A circuit which could clean or ignore the noisy
>signal from the microswitch seems to be the easiest out.
	(relating to multiple counters running slowly; less than 10 Hz)

	Firstly, a microswitch has NO and NC contacts; an S/R flipflop
can be connected with SET on 'NO' and RESET on 'NC' and there will be
no bounce in the flipflop's output.  This, however, adds a third wire
to the switch connections.
	How about getting a large parallel port (boards with 144 inputs
are probably not feasible, but three PC plugin boards with 64 circuits 
each would be suitable) and just strobing them in software?  With a 
60 Hz clock, add to a (software) counter every time a switch goes high
for at least two consecutive cycles after being low for at least two cycles.
	The PC could even do something else in its spare time, if the
clock were connected in interrupt fashion.

I am known for my brilliance,             John Whitmore
 by those who do not know me well.