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Easy to use Household Temperature Monitor?

Posted by Cliff on from the creating-a-better-thermostat dept.

Jim Carroll asks: "I awoke this morning to a gas furnace that conked out. The house was 60F. We had to turn the switch off and on to get it working again. Fair enough -- but I'm worried about it going off when I'm travelling and having the pipes freeze. I'm looking for an inexpensive, simple to use temperature monitor/sensor that would plug into a USB port, that would then log household temperature to a server, so that I can view it through my broadband connection while travelling. Sure, there are all kinds of complex X10 solutions; there seems to be a few kits out there; and some high end industrial applications, but these all involve spending a few hundred dollars. I want simple, straightforward, cheap -- plug it in, and it dumps the temp every few minutes to a file. But there doesn't seem to be anything that is simple, $10-20, that is consumer oriented? And if not, why aren't companies yet making this type of device?"

8 of 106 comments (clear)

  1. Dallas Semiconductor by Y+Ddraig+Goch · · Score: 4, Interesting

    Try Dallas Semicondictor's iButton technology (www.ibutton.com). You should be able to get an iButton evaluation kit for $30-$40 (US). Nice thing about the iButton is that if the power goes off it can still log time/temperature.

    --
    Meddle thou not in the affairs of Dragons, for thou art crunchy and with most anything.
  2. Build One? by semaj · · Score: 3, Interesting

    Why not just put one together with a temperature sensor IC connected to your parallel port? I'm sure there are dozens of simple examples of how to wire them up around.

    This site has schematics and the pros and cons of various sensors.

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    Meep meep
  3. Just a Thought by WavyGravy-R5 · · Score: 5, Interesting

    One idea would be to buy a thermal monitor for your motherboard, like the after market ones used to stick between your heat sink and cpu. With this, you could plug it into your motherboard, have it go outside of your case, and to the outside air. As far as logging the temperature, you could use Motherboard Monitor 5 for instance, which is free. It can compile all of the statistics, including the temperature you want to record, into a HTML file. Then, just make sure it compiles the folders in a directory you can see, and viola, you'll be able to see your house temperature no matter where you are.

    1. Re:Just a Thought by mjpaci · · Score: 2, Interesting

      Take WG's suggestion one step further and have your machine call your cell phone every hour if the temp drops below a certain point (say 55 degrees F) until you log in and clear the alert.

  4. sump pump by theIG · · Score: 5, Interesting

    I remember back in september, Tad Truex wrote an article about how he used linux to monitor the sump pump in his basement. He created a small device that made use of Lorentz Force, which he attached to it's power cord, and as he describes, "The voltage induced on the surface of the conductor in this direction is proportional to the magnetic field strength and therefore can be used to detect its strength.
    Anyway, he then connected it via a db-9 serial port, and wrote a /proc filesystem driver to create something like
    /proc/sump
    Which read as either 0 or 1, depending upon weather the sump pump was on or not. Then on his webserver, he wrote some cgi to retrieve /proc/sump's value when a web page was requested, and used that to create a status report page. It was pretty neat, and while I know your problem is a little more complicated, there is a similar solution. It just involves different priciples, and I'm just a lowely programmer.
    here is the orriginal article
    -kyle

  5. simple by f0rtytw0 · · Score: 5, Interesting

    step 1: buy something that displays the temperature
    step 2: buy a webcam
    step 3: place the temperature display in a well lit area and point the webcam at it.

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  6. Right tool for the job. by orangesquid · · Score: 4, Interesting

    The way this has been done for years is to plug a thermistor straight into the joystick port. The PC uses a one-shot astable multivibrator (did I get that right? I always screw up the terminology) which oscillates with a frequency inversely proportional to a resistance, and the period is measured (in software) to determine the resistance. You can then use a lookup table or interpolation curve to get the temperature. Have a process that asks for real time priority (so it doesn't accidentally miscount/mismeasure the hardware data), stick it in crond, and there you go.

    I don't know of a USB solution, but what about a USB game port (do such things exist)? Surely they wouldn't be very expensive.

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  7. Re:space heater by cdrudge · · Score: 2, Interesting
    My ups ran my fridge for three days in the summer, there is no reason i can think of that it cant handle my computer for a week.
    You never have used a UPS have you? You aren't going to have a UPS that will run your PC for 5-7 days. Well...let me rephrase that. You aren't going to run a regular desktop PC for 5-7 days without spending several thousand dollars on a UPS and batteries. To keep my little OptiPlex GX150 running without my monitor, I'd need one of these and two of these for a little over $2,000 total. And that's just for 48 hours of uptime. At that point, you could just hire a house sitter or just fix the thermostat.

    And I doubt you ran a real fridge off of a UPS for 3 days straight, actually used it, and kept food cold.