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Topic: LM335Z - Temp Sensor (Read 1 time) previous topic - next topic

Roderz

Hi all,

I've picked up a couple of Temp Sensors(LM335Z) thinking, i'll make a simple thermometer with it. I started reading the datasheet(http://www.national.com/ds/LM/LM135.pdf) and now have no idea how to hook this up. I trawled the web for a while but think i've just confused myself even more.

so...
Question 1
How do these sensors work?
Question 2
How do i hook it upto the Arduino?

thx in advance :)

pluggy

1, they output a voltage that is proportional to the temperature.

2, you wire the output to an analogue pin on the arduino (as well as ground and 5 V) and determine the temperature from the reading from the analogue pin.  

If your 5V isn't exactly 5V it may be some way out........
http://pluggy.is-a-geek.com/index.html

Roderz

Thanks for the speedy reply pluggy.

So would i connect both 5v(from Arduino) and the Analog pin to the same point on the chip, being the center pin after looking at the datasheet?

flyboy

What he was saying is that you can use the Arduino power supply (+5V) to connect to the power pin on your temp sensor.  Ground on the temp sensor goes to ground on the Arduino.  Analog pin on the temp sensor goes to the analog pin on the Arduino.  Does this help clear it up?

mowcius


Roderz

#5
May 11, 2010, 12:21 am Last Edit: May 11, 2010, 12:26 am by Roderz Reason: 1
thanks flyboy and mowcius, but I'm still confused as to which pin is the analog pin on the chip. Looking at the datasheet, the LM335Z has the following pin configuration.

left pin - ADJ
Center pin - V+
right pin - Gnd

from what i understand, the adj pin is for calibrating only. :-/


dilbert98122

I think the other posters are thinking of the LM35 which uses three terminals.  The datasheet for the LM335 says it works like a temperature-dependent "2-terminal zener diode".  So, ignore the ADJ terminal.  Connect the Gnd terminal to Arduino ground.  Connect a resistor (Say about 1K) from Arduino 5V to the LM335 V+ terminal, and then connect that point to an Arduino analog input.  Then you should be able to read the analog input and scale the value into real temperature.

mowcius

Yes, sorry, I did not read correctly, dilbert appears to be right.

On another note, dilbert is the name of my hard drive :P

Mowcius

Roderz

Correct you are dilbert, connected as per your instructions and whollar worked 1st time. Thanks a million. :)

Now onto converting my output into something more readable.


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