Subject:
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Re: Help with connecting pyroelectric sensor
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 7 Sep 1999 13:42:14 GMT
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Viewed:
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398 times
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<lego-robotics@crynwr.com> wrote in message
news:84e2ed7a.25059866@aol.com...
> Which interface should I use, the one with, or without the op amp? How do • I
> connect the reference voltage to the interface?
>
> When looking at the interface with the op amp, I am assuming that I can
> attach two voltage regulators to the +7V lead--one at +5V for V+, and one • at
> +2.5V for the reference. However, the output from the sensor would be a • max
> of 5V, and I don't know how to find the proper value of R1 to show the
> correct sensor range from 0 to 5 volts.
You need at least part of the circuit with the opamp. All the diodes, C1
and R1. I doubt you need a +5v regulator for the supply, but you need a
2.5v reference. Maybe you can just use a resistor divider for that. I
can't tell how much ouput the thing makes, so you may need the opamp.
Normally R1 is a 1K. BTW the block diagram for the part shows the reference
and output reversed.
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Message has 1 Reply:
 | | RE: Help with connecting pyroelectric sensor
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| (...) I'd use one of the little reference diodes that make a precise 2.5 volt level from a dropped Vcc. I think it's an LM375-2.5. The reference is probably there to guarantee a certain output for a certain range, independent of the supply voltage. (...) (25 years ago, 7-Sep-99, to lugnet.robotics)
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Message is in Reply To:
| | Help with connecting pyroelectric sensor
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| I am hoping that some of you electronically-minded people can help me out here. I just bought a pyroelectric sensor, and since it cost almost $50 USD, I don't want to break it. I want to connect it to the rcx, but it's not as simple as I'd like it (...) (25 years ago, 6-Sep-99, to lugnet.robotics)
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