Subject:
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Re: light sensor multiplexer
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Sat, 31 Mar 2001 19:38:54 GMT
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Viewed:
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2018 times
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hi Nitil,
that's a nice and simple cirquit, but isn't there anything wrong with the grouding ?
Nitin Patil wrote:
> Hello to every one....
> all the time I was promising to put up ckt Digram
> for time being I have included hand drawn Ckt
> visit
> http://www.geocities.com/mindsensors
>
> FET I am using are low thereshold FETs
>
> In lugnet.robotics.rcx, Stef Mientki writes:
> > Hi Nitin,
> >
> > thanks for your information.
> > You know, by asking questions, you'll get the answers often from yourself. Just when I posted the question to you, Eureka. But let's be fair, you were the one who triggered me.
> > I've adapted (without the power reduction) the zener diode and it works fine and saves energy.
> > I've to do some little programming and I've still plans to post my sensor multiplexer this week.
> > I'll stay currious about your design, maybe it contains some other nice tricks.
> >
> > Nitin Patil wrote:
> >
> > > Hi Stef,
> > > sorry for little late.
> > > What I am doing is that I need to get the voltahge down and most efficient
> > > way of doing that without losing swing ( if you divide you lose swing too)
> > > is level shift it and you can do it by putting by Zener. I need levels of 0
> > > V to 2.5V. you can solve your problem by using lower Vcc for your CMOS
> > > devices. this will get you lower hi/low levels.
> > > I am using PIC for logic. which is much more flexible that counter, but
> > > that is not a bigger problem.
> > >
> > > I was thinking of drawing th ckt in CAD and post it but I think I will just
> > > scan it and post it .
> > > regards.
> > > Nitin
> > >
> > > In lugnet.robotics.rcx, Stef Mientki writes:
> > > > hi Nitin,
> > > >
> > > > I'm an energy freak to, but I can't follow your reasoning
> > > > Because I'm building a multiplexer too (probably will be posted next week, so I can make still some changes) and I'm using even lower resistor values then Michael (due to a transistor inverter) I'm very interested in your design.
> > > >
> > > > Nitin Patil wrote:
> > > >
> > > > > In lugnet.robotics.rcx, Michael Gasperi writes:
> > > > > Ok I agree what you say about time constant of your RC
> > > > > But still by using such low resistance you are wasting power. almost 1.5 mA
> > > > > is flowing through this 4.7K.
> > > > > you can keep RC constant and increase R that should improve performance.
> > > > > what I do is I have 5.2V zener in series with 120Kand 10pF this takes
> > > > > current of 40MicroAmp.
> > > >
> > > >
> > > > Using CMOS IC's, feeding it from 7 Volt (NiCd cells), you have to switch the output (for a reliable operation) at least from 7V-1.5V=5.5V downto 1.5V, resulting in a swing of 4 Volt.
> > > > Using a zener of 5V2, the maximum swing you get is 1.8 Volt in a totally wrong region.
> > > > What am I missing ?
> > > >
> > > > >
> > > > > >
> > > > > > "Nitin Patil" <gn1721@lycos.com> wrote in message
> > > > > > news:GAKC9v.F5A@lugnet.com...
> > > > > >
> > > > > > > Also what I did not like in your desigh is 4.7K resistor. which changes
> > > > > > > reading in measure cycle.
> > > > > >
> > > > > > With the 0.1uF in parallel with the 4.7K, the voltage on the clock circuit
> > > > > > is still above the measurement voltage during the normal read interval. It
> > > > > > doesn't effect the reading because the diodes are reverse biased. The 4.7K
> > > > > > only comes into play when the power is cut by switching to passive. Then
> > > > > > the capacitor is discharged by it down to where it would effect the reading,
> > > > > > but your not reading it then.
> > > >
> > > > --
> > > >
> > > > met vriendelijke groet,
> > > >
> > > > Stef Mientki
> >
> > Stef Mientki
--
met vriendelijke groet,
Stef Mientki
email: s.mientki@ids.kun.nl
tel: 024 361 3905
fax: 024 354 1211
Postadres:
KUN / fmw
171 Instrumentele Dienst
Postbus 9101
6500 HB Nijmegen
Bezoekadres:
F.C.Donderslaan 2
6525 GJ Nijmegen
homepage: http://baserv.uci.kun.nl/~smientki/
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Message is in Reply To:
 | | Re: light sensor multiplexer
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| Hello to every one.... all the time I was promising to put up ckt Digram for time being I have included hand drawn Ckt visit (URL) I am using are low thereshold FETs (...) (24 years ago, 30-Mar-01, to lugnet.robotics.rcx)
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