Subject:
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Re: LM34 temp sensor to handy board?
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 25 Jul 1997 16:50:16 GMT
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Original-From:
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Jeffrey Strauss Morehead <morehead@ece.utexas.STOPSPAMedu>
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Viewed:
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1339 times
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Jeff,
I would highly recommend the LM358 single or dual supply op-amp. It comes
in a dual package and works great on +5v only. The LM339 is a single
supply comparator. There are several manufactures: motorola, and national
both have data sheets on the web.
Also, I did a lab in school involving a digital thermometer. I used a
thermistor in the leg of a wheatstone bridge and sampled the voltage with
an op-amp whose output was tied to an antialiasing filter to the A/D port
of an HC11. I recommend finding your max and min desired range, then
design the op-amp gain such that the output is 0v for your min temp and 5v
for your max temp. It may be different for the HB. I think there are
pullups on the inputs...but this is the gen idea that gives you the best
resolution.
just my $.02
jm
On Mon, 21 Jul 1997, Jeff Keyzer wrote:
> I tried the circuit out tonight, and it works! (Mostly.) I hooked up a
> 1K and a 3K resistor for R2 and R1, for a gain of 4, and the output is
> roughly linear with the input. Still need to do some more testing. I
> ended up having to use a +/- 12V supply for my 741 op-amp; it couldn't work
> with a single 5V supply at all. I'm going to start searching for some good
> single supply op-amps with rail to rail operation (the LM660 is one, I
> believe), and perhaps I'll be able to get rid of that extra op-amp power
> supply.
>
> Thanks a lot for the help!
>
>
> --------------------------------
> Jeff Keyzer
> UCSD EE Major
> jkeyzer@ucsd.edu
> http://sehplib.ucsd.edu/~jkeyzer/
>
>
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Message is in Reply To:
 | | Re: LM34 temp sensor to handy board?
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| I tried the circuit out tonight, and it works! (Mostly.) I hooked up a 1K and a 3K resistor for R2 and R1, for a gain of 4, and the output is roughly linear with the input. Still need to do some more testing. I ended up having to use a +/- 12V (...) (27 years ago, 21-Jul-97, to lugnet.robotics.handyboard)
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