I realise this has been asked before but the questions seem old and the answers dated. Does anyone know of a USB thermometer which is likely to work with Linux easily -- to be plugged into a Pi to keep tabs on ambient temperature?
I see loads of USB thermometers but the only one that comes up on Amazon when I search using Linux in there looks very strange indeed.

After searching amazon you should look into their sites for linux support.

Indeed, but there are hundreds of items listed on Amazon and after some googling I get the impression that some are supported by a Linux driver which may not need manufacturer support. So, I am asking here in the hope that somebody is using one right now and knows it to work.

Hi,

Look at this project: http://www.raspberrypi-spy.co.uk/201...ometer-sensor/

hope this helps.
Have fun & enjoy!

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Thanks, I've avoided things like this because I can't solder but that looks like it doesn't require it so I might manage it.

Hi,
Soldering is a learned skill. Practice, practice and practice some more!
Good learned techniques go a long way.

Here's a good tutorial: http://www.aaroncake.net/electronics/solder.htm
Hope this helps.
Have fun & enjoy!

I have used a 1-Wire sensor which was well supported under Linux (apt-get install digitemp). Have a look at http://www.ibuttonlink.com/pages/temperature-sensors.

Here is another one which I do not have any experience with but it seems to be well supported: http://www.yoctopuce.com/EN/products...to-temperature

And as someone who is 'self-taught' may I suggest you raid every dumpster and car-boot sale you can find for old discarded circuit boards to use for practice.



As to the original question, on an RPi a homebrew solution is definitely the way to go. Simple sensors like temperature and light sensors don't require complex processing whereas USB is inherently complex by nature. The only reason to use USB for them is when you're using a 'standard' PC that only has USB as an option.

Hi,
Yes, a good idea if you want to learn how to make repairs. Re-soldering is a difficult task. You need to be certain that everything has been removed. I like to use a solder-suck tool but sometimes must use a solder-wick. Some boards may have a sealer(conformal coating) that will have to be removed before doing anything to the board. I would recommend students to use breadboards for practice. That way they would need to follow good preparation techniques for installing sockets or even feed through wires for a circuit. Even the need for proper heat sinking with active devices like transistors or special components. You do not want to experiment using a expensive device for practice.

I think the use of USB is not a problem when interfacing if the experimenter prepares their project with required support hardware. RaspberryPi, Arduino and other single board systems do have specialized interface support subsystems for interfacing USB with their systems. Arduino has the 'shields' that can be used to create your interface. Simple breadboards that have solder pads with mating headers for the Arduino board. Same is true for the Rpi. I find that USB is a good interface option that can be easily done for Rpi, Arduino and other SBC. Not just for PC interfacing but any interface that can be handled by the Universal Serial Bus (USB). At one time we were restricted to use a Data bus interface then for long line use RS232 or RS485 to communicate. Since the mid 90s' we could use USB as long as both devices supported the interface. I've done my share of interfacing systems and would have loved to have embedded devices years ago to ease the design cycle for the interface. Today's technology is very exciting to me, I've been using both the Rpi & Arduino based designs for a while now and just love the techniques available. ODROID-C1 is one device that I will be using in the future since the specifications and cost challenge the Rpi & Arduino for new designs;USA Vendor price is now $36.95 single unit price. Be sure to look at the full sub-system support for this embedded device.
Have fun & enjoy!

1 members found this post helpful.

I appreciate the ideas for "making my own" and I will only comment that I have tried soldering on a good few occasions and found myself lacking in the requisite accuracy and consistency. Sadly I've not the most steady hands nor the most careful.
Aside from the above I do also ask about USB as I'm not really looking for a project to use the Pi so much as a sensor I could plug into it, my desktop, my laptop or any other and use it. Apologies if this wasn't so clear and my assurances that I am looking at the various none-USB solutions suggested.

Hi,

You could use the printer port as input. Other construction techniques can be used, look into wire wrap technique. If you do not want to use the integrated temperature sensor for readings then you can construct a simple thermistor probe that is constructed inside a small copper tube. The wire extension leads soldered to the thermistor bead leads then shrink wrapped separately to insulate electrically then place the probe inside the tube that is sealed on one end with a cap. You would need to crush some glass ( I use beer bottles). Break the bottle inside a coffee can then you can create a finer glass with a small piece of metal in the bottom of the can then crush the glass with a hammer or even a piece of black pipe that has a screwed on cap. You are basically using the pipe & can as a Mortar and Pestle technique to crush the glass. Once you have the larger pieces crushed you can move that glass to a heavy grade freezer bag then use a hammer to crush the glass to a finer powder. You would then use the glass powder as a thermal transfer surrounding the bead thermistor to get a uniform temperature transfer. I would first place a small amount of the glass powder inside the tube then place the thermistor and then pack in more glass. To seal this you can use two part epoxy.

You would need a preamp circuit for the thermistor and then a ADC(Analog to Digital converter) to get a digital word that represents the temperature. Another transducer circuit with good calculation & descriptions.

A good transducer interface with ADC using the printer port for Linux. I setup a simple transducer interface for a temperature probe for LAB usage. Worked well with the printer port since your updates in temperature would not be that quick. Your measurements could be over a period of time to show rise/fall. To calibrate the probe and circuit, you can use a ice bath and the thermistor specs to calibrate the probe.

You can use wire wrap technique to construct the circuit on a small perf board since the frequencies are small for this type circuit. Be sure to use a clean +5 Vdc power supply.

Very doable project!
Have fun & enjoy!

Well, back to the original idea of a USB connected device, there is at least one device on Amazon that is confirmed to work under Linux. (it implements an HID interface)
And I did find one other device that might work, though I can't tell for certain what protocols it uses.

If greater precision is needed, I still think a home-brew device is the better option though.

That looks like a nice option. How would you read from a HID device using a daemon or cron script? At the moment I have a headless server running Zoneminder and I have a cron script which runs every few minutes:
How would you implement that with a HID device? I imagine you could read from /dev/console?

Sorry for not responding sooner -- I've not been using a desktop PC so not able to check out the device suggested. It does look like the kind of thing I am looking for.
Sorry, tend to aim for brevity and forget to mention such things as this is intended to measure room temperature at home to check that the heating isn't going on in the middle of the day and that kind of thing. I can SSH my Pi and wake my Desktop from it so it's something I would like to be able to check.
I'd also like to be able to register ambient temperature on a laptop, for example, (through a long enough extension cable) for trips abroad and the like.
I have a device which displays inside and outside temperatures and humidity but it is, sadly, not computer connected so I would hope to do this via computer also.

Since posting this I went the whole hog and purchased a Netatmo "home weather station" thingy -- basically outside and inside temperature and humidity gauges connected to the internet. Expensive, silly but a kind of amusing.
Recently, however, I purchased an Arduino Uno "Super Starter Kit" in which is a temperature and humidity sensor. The included tutorials do include code to output the readingsto the serial tty but, for some reason, even using some tty settings I found on the web I can't set it up so that I can just plug the Arduino in and read the temperature from the tty it creates.
Still, the whole kit was less than half the price of the "weather station", I'm learning a little and there are more option for things like LCDs and LED displays. So, turns out an Arduino may be the answer if I can figure out how to read the serial.print and serial.println properly.