Remote Thermometer Using Arduino


[Peter] sent in this writeup on how to build a remotely accessible thermometer. The hardware side is pretty easy on this one, all you need is an Arduino, a resistor and an thermistor. The software is where the main focus is.  You can check the temperature via command line, but also via email. It can also tell you the temperature using the host computers sound hardware. You can see a video of it in action after the break. We have to wonder why he didn’t make it twitter.


24 thoughts on “Remote Thermometer Using Arduino

  1. I love these kinds of projects. While the hardware aspect of this one is ridiculously light (a resistor and thermistor…), the follow-through on code is nice. I plan on using the arduino platform for a full redo of my home’s heating system.

    Any thoughts folks?:
    – Nokia N810: wall mount this tiny computer
    – Web server: install a small web server on the N810
    – Temperature sensors + XBee: sense temperatures with some regularity (minute by minute? 5 minutes?)
    – Arduino: concentrate the serial signal from the XBees, located throughout the house
    – Relays: I need to better understand how the relays in my hot-water radiative heating system work, but I’m pretty sure all I need to do is close a zone’s circuit to turn it on, and open a zone’s circuit to turn it off.
    – Code: this will be the long pole in the tent. While I’m a pretty good coder, it’s been ages since I’ve written anything but net code (php, js, java, mysql). Gotta make an interface with arduino to read data and display it on the (private) web.

    This will allow better charting of my temperatures throughout the house, allow me to segregate zones, better understand their interplay, etc.

    Anyone wanna play?

  2. man, i had actually mocked up a nearly identical prototype except it used a (admittedly kludgey) python script to send the results to twitter. i just set it aside and forgot about it.

    curse you [peter]!

  3. i am working on a project similar to this to do monitoring of beer vats during the brewing process. only I am tapping into an existing temperature control system rather than using a thermistor. and i am transmitting via xbee to another xbee then to the web. hopefully it will be done soon.

  4. @scabby:

    net code is all you need.

    for serial you could use python, everyone does. or even use flash (as2 is just javascript)

    there are serial servers for audrino and flash if you google for them.
    basically it allows flash to talk through a serial port to audrino.

    php can talk via serial as well, but it’s slow as it requires a page refresh everytime. flash can refresh 24 times a second if you need. or more.

    also, the nokia tablet seems underpowered for no reason.

    why not an msi wind or any other netbook?
    they’re cheap, run linux or windows, and still small.

  5. damn, I really need to get familiar with the Arduino, it seems like a good way for me to get started with programmable electronics.

    apart from this being an interesting method to probe the temperature, I recently built a little circuit (of which I found the schematics at for probing a DS18S20, which seems to me a cheaper way of accomplishing the same. Also the ease of wiring up an additional 1-wire sensor once you finished that tiny circuit, is astonishing :) having it hooked up to munin (using digitemp), two DS18S20 are now steadily producing graphs each and every five minutes (the resulting image is published at my blog).

  6. @fyrebug, thanks for the comments… I need to figure out some finances before I begin (purchasing components), but I’ve been mulling this one over ever since I moved into this house and started getting $1000/month energy bills. (It’s 100 years old and huge, so while my focus has been replacing energy-inefficient windows, adding insulation (what’s that?!), I’d like to add some monitoring to the equation.)

    The only reasons for the Nokia are that I have one and it’s touch screen. There’s no necessity for it to really run the web server or any of the hardware. I have plenty of other machines that run 24/7 that could perform this task.

    My desire for the N810 is to serve as an interface: it’s small, runs web apps fine, and could easily be wall mounted. I’ve thought about the netbook route, but then I’d have to hack it, rotate screen and add touch capability.

    I think I’ll pick up some hardware in the next couple of weeks.

  7. Neat stuff, but I can think of so many different ways to do this…

    I love the arduino, but it’s not necessary for this type of project. Use two xbee’s, one attached via a serial cable to a computer, the other hooked to the temperature sensing bit. The xbee has built-in IO. Then just use your favorite serial port capable program on the computer to post the information as often as you like.

    Now, if you wanted to eliminate the intermediary computer altogether you could use an arduino (or whatever processor) with something like an xport and just make posts to a server.

    And of course, wiring this to twitter is easy…

    I recommend “Making Things Talk” by Tom Igoe, he covers a lot of what I wrote…

  8. I personally try to stay away from the xbee.

    rentron and sparkfun have some cheapo rf that with a little elbow grease can be run with a $2 pic microcontroller. the rf modules are $5-7. xbee is most deffinelty NOT that cheap…

    audrino is great for prototyping but I can’t honestly be bothered to spend anything more than $4 on a microcontroller. it seems silly to spend 30+ or even some of these uber super duper set ups with multiple ‘sheilds’

  9. fyrebug… i check out sparkfun on a weekly basis and have a keen interest in the RF modules (low cost, hello!), but there’s one significant problem: “Only one 434MHz transmitter will work within the same location.”

    Ideally, I’d like to be able to get one transmitter (with thermistor) / receiver, get the system working (prototyped). Then, get more and more transmitters to be better able to keep tabs on the heat loss in the house. (not to mention long-term security system…)

    as far as those rf transmitters go, they’d be perfect (500 ft range) if i could get 20 of them working at the same time.

  10. ahhh well that is a problem then. my comment wasn’t directed specifically at you though scabby.

    though, you could possibly have RX+TX on each unit you build + a microcontroller and have all but one on recieve, then they run in a loop. 1 transmits, then turns to reciever when done, and so on. working your way through the line of 20.

    20 of those are still cheaper than 20 xbee’s. and it’s the same code+circuit design for all.
    $5+5+2 + board cost +thermo sensor

  11. fyrebug, I never thought of the arduino as a $30 microcontroller. It was a 4 dollar chip with a programmer and usb interface attached. If I had a pic programming kit, and a basic usb board before that, I would have gone that route. For those only now getting into microcontroller projects, the arduino offered a cheaper route than a 70$ or more pic board. Sure, you could build a serial ICP for cheap, if you have a serial port. You could build a USB programmer, if you can program the chip to build it.

    Once you know what you are doing, you just pull out a digikey/mouser catalog and get a hand full of chips for $20 (or as a sample, even better). 4$ even for a surface mount atmega 168 (aka arduino’s cpu) from . . . can’t tell if this is last year’s digikey catalog or an even older one.

  12. @fyrebug – sorry if my post sounded contentious. didn’t mean it that way, but more to say “was looking at those, and i wish that would work.” i’ve been looking into a lot of options, and will be heading to sparkfun’s town this month, so might stop in to pick up some purchases. :)

    @quin – same… i’ve got no idea how to do this. if a quick (dirty) and easy programmer costs $30 and i can get a handle on it, i’ll take that route over fumbling and futzing it up until i’m too frustrated to continue. while i haven’t used an arduino setup yet, it seems like a glory land of easy first steps: tons of code, tons of hardware, and lots of people w/ experience.

  13. An arduino is probably a reasonable choice for a first doodad. On par-ish cost wise is a pickit 2 for pics, $35 for the programmer/debugger or $50 for a board and a programmer/debugger, works with most pics, even the dspics and 24f ones for some 16-bit goodness. Also, you get to use assembly… or c or basic… if you don’t mind buying it, or using the size limited versions.

    Of course, this really has nothing to do with the original post, but it just popped into my head while reading the comments, so here it it.

  14. To continue off-topic…

    An AVRISP is only $34. You can get even cheaper programmers from eBay. And they’re reusable for many projects.

    And the PIC architecture seriously pales in comparison to AVR. There’s really no contest between the two. PIC has cumbersome assembly, no open-source C development tools, generally weaker peripherals, and on and one. Its only advantage is it’s slightly cheaper.

  15. How come that when I access a page on it not only opens the page on port 80 but simultaneously tries to connect via UDP on port 137, are you guys taking the ‘hack’ part a bit too serious?

  16. @quin the problem is the usb etc is always there. I rpefer to only pay for it once. some of my projects require 30-40 pics (objects in different areas of a room etc) so audrino just isn’t efficient for things like that or what scabby is asking about doing. it’s too expensive.

    AVR though as someone brought up… which is what audrino is using… that has always sounded tast and yes, better than pic.

    in the end, different tools for different projects and there’s no ‘best’ tool. just use them all!

  17. scabby – i totally will take you up. But you’re doing it too complicated. I’ve started a local project to do this moar better, and I figured I’d open source the whole load and sell off some kits or something. AIM me at L2D2003

  18. To continue off-topic
    “And the PIC architecture seriously pales in comparison to AVR. There’s really no contest between the two. PIC has cumbersome assembly, no open-source C development tools, generally weaker peripherals, and on and one. Its only advantage is it’s slightly cheaper.”

    well this week I was thinking serious about switch from pics to avrs . So I did some comparison I opened

    and start comparing one by one similar devises, after I get confused and start wondering why people saying that avr so superior to pics, looking on both websites I saw there is no point to compare atmegas to 16Fxxx family but when you look on 18fxxx family thing getting equal and when you look on 24fxx, dsPIC33 and dsPIC33 there is no point to compare them to atmegas because they clearly win by memory price and speed. So I don’t understand this phenomenon how avrs better if simple comparison show different answer, or you guys compare all avr to 16f84? well 16f84 is not only product microchip make actually microchip deserve respect only for continue producing this ancient chip.
    Yes there is no free good c compiler for 16fxxx family but there is reason for that how much c code you can fit into 1-4k of memory ? not much useful program.
    Also I notice in powerful category that there is more pics available in DIP package and only couple atmegas have DIP package and this is serious issue for hobby person.
    And the last one is Atmel attitude to their product, I remember couple month ago they was selling themselves so do they really care about their chips? Or if something else like flash memory will be more profitable atmell will stop making microchips and start doing flash

    So please someone give me good answer, should I consider to swith to avr, point on advantage.Im serious I don’t want war, I want to chose once and improve skills concentrating on one and specific device, just like I chose C++ over java couple years ago after trying both for 2 years

    or all this hassle around Atmel made by funboys? just like around apple.

  19. fyrebug, you obviously have no clue. The ARDUINO (look how it’s written) is a development tool. Once it works you can put the code on a cheap empty Atmega8 or 16 or the new bigger one, throw in a voltage regulator, resistor, a cap and an oscillator on some veroboard and there you have your 30 temp sensors or whatever for 5 bucks each. You don’t need a whole $30 board for every little project. It works just like PICs in that respect.

  20. Sorry, I’m not a native English speaker. Didn’t mean to come across as overly rude.
    Yes, the arduino board is just a convenient way of using atmegas for beginners. Actually the whole arduino project consists of the board, the software and the bootloader code on the atmega which allows easy uploading of your own programs.
    Check it out, you might like it.

  21. @fyrebug – a lot of people agree that there’s no reason to have USB on every board. There are a number of arduino taste-alikes that take the USB off the board, effectively re-partitioning the “standard” Arduino into two parts. If you check out or you’ll find entrypoints in the $10 range.

    it’s very true that embedding $30 isn’t the way to go for many projects, and these fit that need. Check ’em out.

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