Readings

Is there a wireless thermometer that I can place outside and get readings on my computer?

I have a crawlspace and I want to place a thermometer in there where it'll use my wireless internet to take readings and I can retrieve them from my computer. I've been looking online and can't find anything based on different combination of searches.

I have a wireless thermometer and it seems to effortlessly communicate with the various sensors I have placed around the house. I would like to be able to have my PC track those readings. It seems like a simple thing to do since thee data is flying around. The problem is how do I capture the transmissions as the fly by? I assume they are using the 433 MHz frequency. While I am somewhat proficient at PC software development, I have never done any hardware work. I wouldn't know where to begin in capturing this data.

I know there are units for sale from various manufacturers but they usually have propriety software for interacting with it. I want to be able to write my own software. "That's my field of expertise, so naturally that's where I want to play."

It seems to me if I can simply poll the device on some schedule, I can easily record the value I retrieve. The question is, "How do I poll the device?" and "How will it answer?"

I have googled this but found very little. Most of what I have found seems to be industrial and scientific. I am more of a hobbyist looking to scratch an itch.
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Posted by Curt Wuollet on 20 May, 2007 - 2:57 pm
The problem is that you have to know a lot about the hardware and any firmware to do this. And it's proprietary. And even if they are willing to share, it's tough sometimes to find the people who actually know anything. It's unlikely they use any standard protocol because there isn't one. It used to be that you could get a setup from Heathkit or others where the idea was that you learned something, but I haven't seen such things lately. You could make your own without much effort, but the cost would be a lot more than the Walmart units. Most consumer goods these days are truly disposable black boxes. The people who designed it may not have even kept records as they probably did it on a one shot contract. Such is globalization. For a while it was a requirement that foreign electronics came with a schematic at least, but they have even given up on that.

That said, you might have a chance if you can look up the chips on a unit and find the detected data stream and hijack it to a serial interface. But even that is non-trivial, but often doable. There is also the possibility of buying or making a receiver for FM (most are FM) on that frequency and recording the bursts for analysis. It's all about how bad you want to do it. It can be done if you want to badly enough, I've done worse. If you know enough about electronics and computing, it's pretty hard to keep you out. It is fairly easy to ensure that it is not worthwhile
Certain Diodes can work as excellent devices provide highly accurate instantaneous temperature readings .

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&KeyWords=Diodes&x=0&y=0

You might have to is signal for below URL and tranlate thru SW.

http://www.grainger.com/Grainger/items/4LY10

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