What is a good liquid temp sensor that is affordable?

Brann Fenix

Hi,


I am starting to research needed parts for a room and fish tank controller I wish to build with my BASIC Stamp 2. The first road block to stop me is the lack of a sensor that can read the temp of my water. I was pretty sure I read the AD592 Temperature Probe was able to do the job, but at a second look I could not find the info anywhere that said it would or would not work. Maybe I am going blind or just missing something this time around. So, could someone please recommend a sensor for the task of being in the water 24/7 and reading temps in the ball park range of +40F~+90F. Other than that my only other requirements are low cost and using 1 or 2 pins on the BASIC Stamp since I will be running other sensors.


Thanks in advance,
Brann

willthiswork89

This is on Parallax Page for the AD592

Electronic temperature sensor rated is rated: -45°C to +125°C; performance specified: -25°C to +105°C; output is 1 mV/K. This sensor is ideal for submersing in liquid environments. Well documented in our Applied Sensors text.

hope this helps thanks!

-Willthiswork89-

Brann Fenix

Bah... So, I am not going crazy just blind [noparse]:)[/noparse]

Thanks for the super fast reply!

-Brann

Jonathan

Bran,

Here is what I did, and it worked for me. I used a 1/4 inch stainless steel tube. An LM34/35 sensor fits nicely in there. Use a little heat sink grease for good contact. I epoxied (with aquarium OK epoxy) the ends of the tube. On the end with the wire, I also put heat shrink, and shrunk it while the epoxy was still wet. The wire was direct burial telephone wire, so it has some level of water resistance. Of course, the wiire is not actually submerged.

This method costs less than 10 bucks, and is easily read with an ADC connected to the Stamp.

Jonathan

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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot

Chris Savage

I'll second Jonathan's reply...I have also used an encapsulated LM34 in this fashion and they work great.· ADC0831 is an inexpensive method for reading it and we have example source code for this exact application.· Take care!

http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv29.pdf

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Chris Savage
Parallax Tech Support
csavage@parallax.com

Brann Fenix

Thanks everyone!

Those are some great ideas, info and links [noparse]:)[/noparse] I should be putting my order in soon and starting the fun asap.

Thanks again,
Brann