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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Tue, 27 Mar 2001 13:24:01 GMT
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Viewed:
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1785 times
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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
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Message has 1 Reply:
 | | Re: light sensor multiplexer
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| 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 (...) (24 years ago, 27-Mar-01, to lugnet.robotics.rcx)
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Message is in Reply To:
| | Re: light sensor multiplexer
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| 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 (...) (24 years ago, 22-Mar-01, to lugnet.robotics.rcx)
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