USB Thermometer

[vetteguy]

Does anyone know if there is anything available that would be like a thermometer or thermocouple that plugs into a USB port and then could be used to measure ambient temperature in a room? I've googled but not found anything that wasn't a custom job.

 

[dullard]

Yes I do, I'm ordering parts now that have that feature (Note I won't be using that feature since I measure my temperatures with a PCI card.) However the price is expensive: $2900 ($599 + $2199 + $99 for RTD temperature sensor). I'm sure companies make it for less than that, but I don't know them off the top of my head.

 

[vetteguy]

Originally posted by: dullard
Yes I do, I'm ordering parts now that have that feature (Note I won't be using that feature since I measure my temperatures with a PCI card.) However the price is expensive: $2750. I'm sure companies make it for less than that, but I don't know them off the top of my head.

Hmm...yeah, I was thinking more like sub-$100. I'll keep looking.

 

[dullard]

Originally posted by: vetteguy
Hmm...yeah, I was thinking more like sub-$100. I'll keep looking.

It'll run you $30 for a thermocouple. Then you need an A/D converter that uses USB (which is what you should try searching for on Google). The cheapest A/D converter I've seen ran $500ish and it was ISA.

Ok I google searched really quickly and found Model 301 for $350 ($425 with case and USB cable). Also that didn't say its accuracy at measuring the millivolt range. We are getting closer. Too bad so many companies won't put their prices on their webpage. I'll let you call them...

 

[techfuzz]

Originally posted by: dullard
Then you need an A/D converter that uses USB (which is what you should try searching for on Google). The cheapest A/D converter I've seen ran $500ish and it was ISA.

Why not just get a digital thermocouple/thermometer and skip the whole A/D conversion process? Save yourself $300-$400 at least.

techfuzz

 

[dullard]

Originally posted by: techfuzz

Why not just get a digital thermocouple/thermometer and skip the whole A/D conversion process? Save yourself $300-$400 at least.

techfuzz

Do you know of any of these with USB capability? If so, then those may get into his price range. I'm just helping with the best I can do (and this isn't my area of expertise).

 

[vetteguy]

Originally posted by: techfuzz

Originally posted by: dullard
Then you need an A/D converter that uses USB (which is what you should try searching for on Google). The cheapest A/D converter I've seen ran $500ish and it was ISA.

Why not just get a digital thermocouple/thermometer and skip the whole A/D conversion process? Save yourself $300-$400 at least.

techfuzz

I'm interested if you know of any such devices.

 

[Mark R]

If you know electronics, and can program then you could try to design one yourself. However, USB is a real pain to use - as you have to write device specific drivers - and if you've ever tried writing windows drivers, you'll know that it is a nightmare.

How important is the USB interface? Would a serial port (COM port) do? Or even parallel port?

There should be dozens of cheap industrial thermometers with COM ports - plus writing software would be trivial. If you can't find one ready made, then building one would be pretty easy - all you'd need would be a $.50 temp sensor chip and a $2 CPU with integrated A/D convertor and COM port and about $5 of additional components.

You can get USB to serial adpators. That would also have the advantage of not limiting cable length. USB is limited to 15 feet. Serial ports are essentially unlimited - I know of anecdotes of people running a serial cable over a mile (to play multiplayer games - before wireless networking became a reality).

 

[vetteguy]

Originally posted by: Mark R
If you know electronics, and can program then you could try to design one yourself. However, USB is a real pain to use - as you have to write device specific drivers - and if you've ever tried writing windows drivers, you'll know that it is a nightmare.

How important is the USB interface? Would a serial port (COM port) do? Or even parallel port?

There should be dozens of cheap industrial thermometers with COM ports - plus writing software would be trivial.

It probably doesn't matter...and it's not actually for me, it's for our department head. The building he works in has an air conditioner that is insane-it's like 50 degrees in there constantly. He has repeatedly talked to the HVAC people but they assure him it's "not as cold as he thinks it is" (I am not exagerating when I say you can pretty much see your breath in there sometimes). He wanted to put a PC with a temperature probe hooked up into the coldest area and have it log over time how cold it gets so he could show them. I was just curious if there was any easy way of getting the data he wants.

 

[thorin]

Google?

Try here
and more specifically here ( Schematic )
and here
and here
and here

Thorin