(MM) wild temp sensor readings


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TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 4447
Posted: 02:11am 13 Jan 2012      

Pete,
I run 10-15 metre two wire leads to some of my LM335's without any problems.
I feed mine from 5V and pick a resistor to give 1-2mA at 'normal' temperatures.


A 1k resistor or slightly larger for R1 should do the trick.

I have also put in a voltage divider to drop the output a bit and to keep the voltage to 3.3V if the signal lead goes open circuit.
That happens when the wife goes mad with the pruning shears. I have lost a few soil temp sensors that way!

I do usually put a small capacitor at the Maximite inputs and ferrite beads around the cables but I do play with radios as well so it's second nature for me.

Jim

My CGMMSTICK's arrived today so time to warm up the soldering iron...Edited by TassyJim 2012-01-14
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