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Topic: Clarification about LM35* (Read 2489 times) previous topic - next topic

un1x

Mmmmmmh ...

works fine on my Nano, but I've just tried on a Duemilanove I got wrong voltage values.

Voltmeter returns me approx 5.10 Volt and the calculated value is 4.96 ........

This isn't good for temperature measurement.

Yot

So you can measure with 2 meters, which one do you believe? :)
Possibility could be to first measure the internal bandgap with a multimeter/scope and go on from there.

Jeroen.

un1x

I believe in my external voltmeter  :)

jondecker76

Quote
It's similar like my idea, but I can't understand how you can calculate the multiplier.
You try to get the temp value from the temp value. I assume you use the old temperature value and the old known temperature to calculate the multiplier for the new one. Is it right ?


Pretty simple actually. How I am doing it is I go to a calibration screen on my LCD Keypad shield (DFRobot).  I use the left and right arrow buttons to enter the known temperature (which I am getting from a manual thermometer).  The LM35 is in measuring the same thing at the same time.  After I enter the temperature, the multiplier is computed from the entered value and the actual value being read from the analog pin.

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