Connecting LN35 to read negative temperature with arduino?

Other Hardware Sensors
1

Hi experts,

I read in this thread (How to get LM35 to read negative temperature with arduino? - General Electronics - Arduino Forum) that one can build a special scheme to read negative temperatures with LM35. In that thread Wawa says that "you have to measure the output AND the ground pin (two analogue inputs)". I saw Figure 18 on TI datasheet but not sure how to connect LM35 to Arduino? Is it like this:

VCC(LM35) to VCC(Arduino),
Ground(LM35) to Ground(Arduino),
Ground(LM35) to A0(Arduino),
Output(LM35) to A1(Arduino) ?

Thanks.

2

You could request that a moderator move this post to the Sensors topic where it will be seen by members more familiar with sensor issues.

3

gv445:
I saw Figure 18 on TI datasheet but not sure how to connect LM35 to Arduino?

Ground of that circuit (not LM35 ground) to Arduino ground.

  • of the LM to 5volt
  • of the LM to one analogue input
    out of the LM to the second analogue input.

Maybe easier to use a TMP36, which is designed to measure from -50C.

Or the much easier to use digital DS18B20.
They also come in a "waterproof" version, with cable attached.
Leo..

4

Thanks Wawa !