Underwater temperature Sensors

[tmacd]

Hey guys, just a quick question about temperature sensors.

Does anyone have any suggestions for something that can give a an accurate reading of a temperature underwater, fairly quickly? I’ve done some searching, and so far the closest i can come is %100 accuracy, but in 3 minutes, and I’m looking for about 1/10th of that! haha. I’m looking for something that is similar to a probe, something skinny. Cost isn’t really much of an issue, just size and quick, fairly accurate readings. Help me out!

[rovstuff]

tmacd

Try to get a diving computer, the wrist wacth kind, and set it in front of your cam, so you can tilt and get it on your screen. You’ll have accuracy up to 2% inmediatly and it’s not expensive.

Cheers

[rovstuff]

You’ll have accuracy up to 2% inmediatly

2% maximun error.

[rovnumpty]

tmacd

A digiquartz module has a built in temp sensor. No idea of the specs on it.

Think just about all the offshore equipment manafacturers do a digiquartz depth sensor /bathy of some form or other.

The prepackaged units from Paroscientific have a fairly long and thin housing on them.

[Savante]

is this something to go in a manipulator and press up against an object, or do you want a rov-mounted sensor just to tell you the temperature.

the tritech bathy suite definately has an inbuilt temp sensor (about 0.1degree resolution – the manual tells you how to set it up to continuously dump temperature readings up the tether.

I think you can either take the topside pc, have it throw serial data out and have it recorded and timestamped if you need. Might need a little bit of programming, or you could use hyperterminal to record it (but I don’t know if you’d get a time stamp that way).

[Col]

Could try a CTD, depends what you mean by ‘skinny’ though. Think the one I’ve used was an SD1000 or something.

[tmacd]

dive computers were a pretty good idea, we’re going to look at those, but i think we’re also going to try out a thermistor in the end of a hydraulic cylinder, like, drill a hole put it in up to the tip and seal it, that might be the best bet. There’s a hole that is about 2 inches in diameter, and i need to get down about 3 inches and take the temperature, so i think cylinder + thermistor could be pretty cool. I was thinking about something like one of these

http://www.sequoia.co.uk/sensors/Manufacturers/QTI/NTC_liquid_temp_probes.php

Does anyone have experience working with something like these? I’m just wondering about accuracy and time to get an accurate reading.
I’m really hoping to snag a job during the competition from a recruiter, designing and building ROVs offshore, so we’re all trying really hard to build the best one we can, I think we’re going to give the rest of the teams a run for their money!

[liddelljohn]

My brother designs sensors for BOC in the UK he said the Thermister would be a good idea as he used some a few years ago for underwater temp sensors when working for UK water companies.

He also says that there are scientific sensors available from several companies that would also do the job.look at Servomex.

JCL

[TBAR]

Hey T
tmacd said
"Hey guys, just a quick question about temperature sensors………………………………………………………..Help me out!
not being facetious or anything, but, 😀

Turkey thermometer 😯

there’s an idea 😀 😀 😀
there you go, that’ll get the grey matter working
later

[TBAR]

some more information wouldn’t go astray
if you look through your vendors manuals on the system, should have something there for you to start with
plenty of folks sell there gear online
paroscientific is one someone else mentioned
it’ll lead you from there
later

[Savante]

do thermistors exhibit any pressure dependent behaviour ? You can pick up a thermistor for pennies, bond it in scotchcast and put it in one arm of a wheatstone bridge,

tie the output to an rs-232 or usb dac such as that from picotech (well cheap!).

straight into your laptop.

[tmacd]

Thanks for the nod towards thermistors man, I think we’re going to go with that, sounds like the best option for sure, pretty easy to implement, fast, accurate reading, CHEAP. It is basically exactly what I was looking for. and TBAR, I hardly think this is a case of "hey guys, *throws homework down in front of them*, do this for me now!" I had a specific issue that I wasn’t sure about, so i was asking for suggestions, a few good ones were made, a few bad ones, researched them all, which led to thermistors before anyone came flat out and suggested those specifically, I hardly think your attitude facilitates others who might be lurking the board searching for help or answers to questions, I dont think i was unreasonable. You better not get sick of me either, because I’m going to be posting back on this board for the next four months with any questions i have! ahaha

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