Easy to use Household Temperature Monitor?

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?"

Comments

Cookies, beer, and a trinket

[ObviousGuy]

If you are away from home for any length of time, ask your neighbor or a family member to stop in once in a while, especially on cold days to make sure that your house is still in good order. Bribe them with cookies and beer, then when you return from your trip give them an exotic trinket from the place you visited.

Also, keep in mind that 60 degrees farenheit is pretty far from freezing and that the inside of your house is unlikely to reach the temperatures required to freeze the pipes *inside* your home.

Re:Cookies, beer, and a trinket

[VultureMN]

I'd think an even more Obvious answer is to have the switch/thermostat fixed. But maybe that's just me...

Re:Cookies, beer, and a trinket

[Anonymous Coward]

That doesn't take into account the possibility of an actual switch/thermostat failure.

Re:Cookies, beer, and a trinket

[kinnell]

...and if you really need a geekier solution, have him/her enter the temperature into a text file which you can read remotely over the web.

Re:Cookies, beer, and a trinket

[timshea]

Also, keep in mind that 60 degrees farenheit is pretty far from freezing and that the inside of your house is unlikely to reach the temperatures required to freeze the pipes *inside* your home.

Agreed. 60 degrees Fahrenheit is pretty warm for the inside of a house at night during winter. Even my folks, in their 70s, keep their thermostat at 60 at night.

It's not uncommon that it's in the 50s in my house when I've been lazy with burning wood and it's under 30 outside...and I've slept a few hours too long. Lazy me.

Your pipes aren't likely to freeze until it's well below freezing if you keep your cold water dripping - I see 20s outside and high 40s inside before I need to start letting the water drip in the kitchen, which is the longest run of my water piping.

Now when the power goes out, and your pump stops pumping, then you'd better be home to drain your plumbing before it freezes.

Re:Cookies, beer, and a trinket

[HyperbolicParabaloid]

I'm guessing you don't live anywhere that gets cold.
If your furnace goes off, the thermostat isn't involved, and your house will certainly get cold fast. If it is freezing outside, it WILL get freezing inside. And since the water and heat pipes are in the walls, they will get colder faster than the inside of the house itself (if they are in the exterior walls, that is).
And since it can get pretty damn cold at night, your neighbor would have to move in, and stay awake all the time to provide effective monitoring.

Re:Cookies, beer, and a trinket

[tsa]

Mod this waaaaayyy up please! Asking this Ask /. question is a sure sign of terminal geek-ness. I would be very worried if I was your wife.

Re:Cookies, beer, and a trinket

[Anonymous Coward]

Also, keep in mind that 60 degrees farenheit is pretty far from freezing and that the inside of your house is unlikely to reach the temperatures required to freeze the pipes *inside* your home.

Depending on your house, the pipes *inside* your house may be more likely to freeze. The outside ones *should* be buried far enough below the frost line. I lived in an older house that had been retrofitted for indoor plumbing. It had a bathroom the size of a bedroom because, surprise, it used to *be* a bedroom! The pipes were run up through a not-well-enough-insulated outside wall. The landlady had said that I should leave a faucet dripping during the colder parts of the winter, but I didn't believe her. It seemed like such a crime to waste one of the planet's more scarce resources. Pretty soon I gained an incredible amount of sympathy for folks who don't have it like we do.

For the record, the inside temperature (at the thermostat, at least) was about 65 degrees when the pipes were frozen. This had happened before to earlier tenants, so there was a small access opening cut into the wall space where the pipes ran. I had to cram a hairdryer in and run it intermittently over the course of about an hour before the water started flowing again. By the way, we're talking about the edges of Zones 5 & 6 here. Not exactly North Dakota.

After that, I reluctantly left the tap on with just the slightest drip, and that was enough. Moving water doesn't freeze as easily. That winter got even colder for a while, but the pipes never froze again. Needless to say, I didn't renew my lease. Ah, campus slumlords.

Re:Cookies, beer, and a trinket

[duffbeer703]

You must not live in a northern climate. No heat means burst pipes in places like New York, Chicago, etc.

Re:Cookies, beer, and a trinket

[mdielmann]

Also, keep in mind that 60 degrees farenheit is pretty far from freezing and that the inside of your house is unlikely to reach the temperatures required to freeze the pipes *inside* your home.

If he lives in northern U.S, in the Rockies, in Alaska, or any number of places outside the U.S., it is very reasonable to assume that your furnace not working for a day or two will cause your pipes to freeze.

Re:Cookies, beer, and a trinket

[TwistedGreen]

That gives me an idea.

Thermometer + Webcam.

If you use a digital thermometer, throw in some OCR software so you can add some automation.

Re:Cookies, beer, and a trinket

[Spamlent Green]

I agree -- appears you should fix the basic stuff first before adding nifty gadgets to the mix. Clearly there's something wrong with your swtich/thermostat.

Re:Cookies, beer, and a trinket

[confused one]

And that would have to qualify for most boring web cam on the web.

Re:Cookies, beer, and a trinket

[Anonymous Coward]

Also, keep in mind that 60 degrees farenheit is pretty far from freezing and that the inside of your house is unlikely to reach the temperatures required to freeze the pipes *inside* your home.

Indeed.

I recently had a house for sale in Salt Lake City. I still had the utilities on so I could use the place while fixing things, etc. I left the thermostat at 42F, figuring that a 10-degree buffer from the freezing point would be sufficient. It worked like a charm, in spite of several hard freezes before the place sold.

This, of course, doesn't address the real question: what if the heating systems fails? Depends on the climate, location of pipes, and construction of the house. The house I sold was 1925 brick rambler, with a large south-facing wall with many large windows. Given the sunny nature of Utah, it would take several days of sub-freezing temps for the house to cool to the point of busting the pipes.

I currently live in a 1908 Victorian-style (frame) fixer-upper (pretty leaky, drafty, etc.). We have the thermostat set to about 60 at night, and we've had the water run to our bathroom tub (just the tub, not the sink or the toilet) freeze on us several times, but not bust.

Re:Cookies, beer, and a trinket

[erpbridge]

Well, if he's got an old house (like the 1800's farmhouse I'm renting) where the basement is poorly insulated, or not at all, the upstairs temperature could read 55 and downstairs it could be 35. These types of houses don't get heat downstairs, and the pipes, if not properly insulated, do develop cracks.

I learned the hard way this happens the first year I was here, with about 4 leaks showing up that winter. Luckily they were pinhole or small crack, but still... Oh, and btw, it pays to have a cat. My first indication there was a leak was when the cat was standing near the basement door for two days, just standing and listening. Something about the hissing of the leaking water perked her ears up.

Re:Cookies, beer, and a trinket

[dar]

Could be even worse - I wouldn't be surprised if it was the pilot. Do you have an electric pilot? If so, have it checked out now. You don't want that kind of trouble.

Re:Cookies, beer, and a trinket

[allism]

It doesn't even need to be the northern US - my pipes froze after one night of cold weather in central Oklahoma. S/he must live in Florida or something...

Re:Cookies, beer, and a trinket

[cloudmaster]

What kind of moron puts the water pipes in exterior walls? That's like, lesson #2 in "building a house, 101" - "putting the plumbing in a reasonable location". (lesson 1 is "how to use a hammer")

Re:Cookies, beer, and a trinket

[HyperbolicParabaloid]

yeah, you're right. That was a kind of meaningless detail I shouldn't have bothered to add.
(btw, lesson #3 is "when doing electrical work, where rubber-soled shoes, and keep one hand in your pocket.")

Re:Cookies, beer, and a trinket

[cloudmaster]

"but, the only way I can reach that outlet is by standing in the bathtub" :)

Use the internal temp monitor in your PC

[dregs]

I am sure with a little bit of work you can figure out ambient temperature by measuring the temperature of your PC CPU. and working out how it compares with the ambient temperature

Re:Use the internal temp monitor in your PC

[acceleriter]

Or run a few Athlons, then it won't matter if the furnace goes out :).

Re:Use the internal temp monitor in your PC

[bhtooefr]

Actually, the Pentium 4 puts out 10 more watts. So, run a few P4s!

Dallas Semiconductor

[Y Ddraig Goch]

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.

Re:Dallas Semiconductor

[CharlieG]

Or go simple, look up aag electronics, by the Temp module (which is iButton) and go from there

Build One?

[semaj]

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.

Re:Build One?

[x00101010x]

For energy savings programs that I work on we use a very simple homebuilt temperature sensor.

It's just a thermistor (thermally sensative resistor, looks like two thin wires with a small red ball of plastic like substance in the middle) connected to an circuit that converts the current reading to a frequency, the frequency is then read by whatever the brains of the project are (usually a lame-ass PLC (like Idec's MicroSmart line) or soon a customised EtherNut). I'm sure you could also plug it into a parallel port and a little software to read the frequency of the pulses and convert to actual temperature and publish an html document to the web should be all you need.
Another post mentioned something that sounded similar but skipped the custom circuit and just jacked into a gameport. I'm guessing that a gameport does the same thing the circuit we use does and converts the current (from a POT in the joystick) to a useful digital value.

Now, you wanted a simple, off the shelf solution? Maybe try starting a sourceforge project for the software to convert thermistor data over joystick to a published html page. Post it and the programmers will come (maybe, i'm still a noob to the OSS community). All you would need for testing would be a POT stuck into the gameport.

Or...

[mjpaci]

Get an alarm system from ADT. They have all kinds of monitoring as 'value added' services. Things like CO, basement water sensors, temp sensors, fire sensors, smoke sensors, and intruder alert sensors. I'm sure you could build an open source LINUX solution with USB, serial, parallel, and apt-get.

Or, have a neighbor pop over and check once a day.

Re:Or...

[Glonoinha]

Get the monthly ADT monitoring to go with you ADT system and have them call you if the temperature goes below a certain range. Good idea mjpaci.

Just a Thought

[WavyGravy-R5]

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.

Re:Just a Thought

[mjpaci]

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.

Re:Just a Thought

[plover]

My reaction to that is the wires don't come long enough to get far enough away from my Athlon. I have the vent closed in the room with the computer, and it keeps it a comfortable temperature through the winter. For reference, the bank thermometer outside my window currently reads "0F".

I'm just afraid the "outside air" would be too locally warmed.

space heater

[wowbagger]

There is a fundimental flaw in your idea, which is why no-one has done it:

OK, you have a module plugged into your USB port providing temperature to the computer. Oops, the computer has crashed - now who takes care of the problem?

OK, the computer has rebooted, and sees that it is too cold in the house - the furnace has failed. OK, so now what does the computer do - start crunching SETI@Home packets to heat the place?

OK, the computer emails you. The email goes out, and then the computer picks it up and throws it into your mail queue.

OK, you don't have the computer getting your email - you get it via Webmail. So, your computer is in Ohio, and you are in Hawai'i. Now, what do YOU do about the furnace?

There is already a solution to the problem of keeping your pipes from freezing - it is called an electric space heater. Set it to 45 degrees. Place it in the basement away from any flammable items. If the furnace fails, the heater will automatically keep things from freezing.

Sure, a long term power outage will prevent this from working. Guess what - it would also prevent your computer from working. Yes, a UPS will keep the machine running for a while - how many minutes?

The other solution is even more ingenious - it is called "a neighbor".

Lastly, if you WANT temperature monitoring for your computer - look at Dallas Semiconductor's One Wire system. They have cheap sensors that will report the temperature over 1 wire - a little programming on the parallel port and you can read them.

But really, try the simpler solutions first. They will work better.

Re:space heater

[Leffe]

OK, you have a module plugged into your USB port providing temperature to the computer. Oops, the computer has crashed - now who takes care of the problem?

I don't think we are talking about letting Microsoft Windows handle this :)

This scenario is more likely though:

OK, you plugged an USB cable in, the computer crashed, who is now going to cook?

Linux is the way to go for crazy projects, just don't forget to pay SCO the $699 fee or you'll be in trouble.

Re:space heater

[jjshoe]

OK, you have a space heater that goes up in flames and causes just enough flame for the neighbor watching the house to call the fire department. You now have a broken down door, a basement turned into an ice rink from the water used to put it out. No electricity, and no heat.

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.

Re:space heater

[Red_Winestain]

But really, try the simpler solutions first. They will work better.

Ever heard of redundancy? Wouldn't it be nice not to rely on only 1 process working? Neighbors get bored visiting a house daily, so maybe they change to weekly visits and 6 days go by before they notice anything. Maybe there is a 2 foot snow storm, and they simple cannot visit the house. Maybe they get sick and go to the hospital. Maybe they win the lottery and go to Tahiti. These are similar to all the objections you had for the OP's request.

A backup is useful. Given a reliable OS that doesn't crash, a decent UPS, you should be able to get a cheap, effective solution. That's what the OP wanted.

Re:space heater

[Txiasaeia]

Another vote for a space heater. I've got one with "Frost Watch" that automatically turns on when the temp is at or below 4oC; it doesn't even need to be running all the time in order to make sure that those pipes don't burst. Yay! (it's a black & decker)

Re:space heater

[cdrudge]

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.

Re:space heater

[jjshoe]

You dont have to beleive me, that's not the point. The point is no matter how simple of a plan you come up with there will always be something that can go wrong.

Why not?

[sweede]

1) There probably is 0 market for this device.. no wait, 1 person market.
2) you couldnt hope to get something like this without spending lots of money (well more than $10)
3) if you have any EE experiance or even PIC programming experiance, you could whip one up yourself using some schematics found here, http://www.commlinx.com.au/schematics.htm and learn some basic RS-232 programming, then get yourself a serial to USB converter (around 40$) or just use the standard serial port instead.

Re:Why not?

[Anonymous Coward]

Thats a load of shit. there is a huge market for sensors, especially simple ones. easy to use and usb? of course there is a market. its not as common for reasons of legacy, bc usb is young. once it's stability is more proven you will see more sensors being built to it.

Re:Why not?

[LWATCDR]

"3) if you have any EE experiance or even PIC programming experiance, you could whip one up yourself using some schematics found here, http://www.commlinx.com.au/schematics.htm and learn some basic RS-232 programming, then get yourself a serial to USB converter (around 40$) or just use the standard serial port instead."
There are a lot of Pic and AVR USB parts available right now. Just use one of those and make it an HID and a little programming and you are all set. You could make it USB powered with a battery backup if you want some logging.
For montioring how about a little jabber client? You could jump on your notebook and check how things are going at home. It could also try and contact people on it's contact list if the temp started to drop.
A good electric space heater hooked to computer controled power outlet in the basement could be added or you could just use one with a built in thermostat.
All in all a fun little project if not 100% practical. But then we are techs here. :)

Re:Why not?

[Verne]

IIRC the joystick port uses a crude a/d to measure the resistance of each axis to determine where the stick is at.

Just hook a thermistor (a resistor that changes resistance with heat) up to it and read from the joystick port.

PICs suck.

Re:Why not?

[sweede]

wtf? There is a market for "sensors" and other types of data-logging, but the market this guy refers to there is none. as other posts mention, there is no market because this is an illogical idea.

Re:Why not?

[topham]

The problem with this method is you have to poll the joystick port in a tight loop.

If your doing it under windows you might be ok with the joystick routines, but they may not poll fast enough to get a good resolution. You would be better off putting together a simple circuit to toggle a couple of transistors instead. Even if it setup as an alarm (below X temperature). Then you can poll the button lines instead of the analog, and the poll loop doesn't have to be tight.

But, since he isn't looking for accuracy he should be ok anyway.

Me, I much prefer the Dallas Semiconductor method; use their 1-wire devices and their serial adapter. (maybe they have USB now?). I have 2 temperature probes from them, 1 you poll for the temperture, the other has a real time clock, can log temperature at configurable intervals, etc. It has a built in battery and can log a significant number of temperatures. Can log maximum and minimum temperature events, etc. (This particular device could, for instance, be attached to a crate and then checked at the receiving end to verify the crate was not subjected to unusual temperatures. Each device has it's own serial number as well.).

sump pump

[theIG]

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

K.I.S.S.

[Spock the Baptist]

Turn on a couple of faucets to drip.

Re:K.I.S.S.

[jpmkm]

I agree. Unless the pipes are fully insulated the entire length, they can freeze regardless of the temperature in the house. A lot of times kitchen sinks are on exterior walls, so those pipes will be the first to freeze.

simple

[f0rtytw0]

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.

Re:simple

[Anonymous Coward]

And with a little coding you can probably write something to examine the image and translate the temperature into a number (I think this would be easier with a nice big digital thermometer).

Re:simple

[DaoudaW]

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.

Ah yes, the old optical coupling trick..

Right tool for the job.

[orangesquid]

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.

Re:Right tool for the job.

[Anonymous Coward]

Close.

I think it's a monostable multivibrator. It doesn't oscillate, you just set it and time how long it takes to reset. I actually hooked something up to my joystick port with a broken diode (reverse biased) that just happened to let through current proportional to temperature (when it should have been on the order of micro/nano-amps or whatever).

long getreading(short int which) {
struct timeval before,after;

outb(1,0x201); // Poke the monostable multivibrator ;)

gettimeofday(&before,NULL);
while( (inb(0x201) >> which) & 0x1 ); // Time until the axis is clear
gettimeofday(&after,NULL);

if(after.tv_sec > before.tv_sec) after.tv_usec += 1000000;

return (after.tv_usec - before.tv_usec);
}

Very useful

[isorox]

so that I can view it through my broadband connection while travelling

So you find out your pipes are in the process of freezing, but havent frozen yet. You're in Japan. what you gonna do?

Re:Very useful

[Acidic_Diarrhea]

I would assume he would call a neighbor, friend, or repairman at that point...

maybe you shouldn't post so early in the morning. :P

Re:Very useful

[FooAtWFU]

You call the oft-mentioned neighbor and arrange for him to go over there and drain the pipes for you?

Try this do-dad

[R2.0]

http://www.dataq.com/products/startkit/di194rs.htm

$25 data logger, analog & digital inputs. Use an RTD for temp.

Fixing the symptom?

[Anonymous Coward]

I think the first thing you need to do is get your furnace fixed so that it doesn't just "conk out".

Monitoring the temperature so that you can tell if it failed is only fixing the symptom of the problem, not the problem itself (which is an unreliable furnace).

No, but seriously

[DevsVult]

Although a number of non-technical solutions to the "pipes freezing while homeowner's away" problem have been posted, no-one's come up with what the guy seems to be asking for: an affordable, easy way to monitor and control household devices from one's home computer.
A general-purpose "home interface" would be useful for all kinds of things if it were sufficiently easy to use. One workable design for such a system would be as a network of cheap boxes that could be set up in each room and networked with 10 Mbit ethernet, which must be pretty cheap now. The boxes would come in standard sizes. Each one would plug into the wall current and have a number of software-controlled 120 volt power outlets and general-purpose sensor inputs. The company selling the room boxes could publish a sensor input specification and prime the pump by selling light, temperature and motion detectors compatible with the inputs on the room boxes.
Back at the computer, the whole network could be monitored and controlled with a scriptable background application. On a Mac, you'd just give the thing an AppleScript interface. The UNIX/Linux driver would have a family of little shell programs that would send it signals. The Windows version would need a monolithic driver application, but c'est la vie.

If anyone knows of such a solution, I'd be interested in hearing about it.

Re:No, but seriously

[Tower]

Hmmm.... sounds to me like...

Mister House

Weather Station?

[herulach]

How about getting one of those home weather stations and just sitting it next to your box? A quick google got prices around $300 though. If youre feeling really cheap you could just buy one of the many Temperature sensing add ons meant for Overclocked PCs. IIRC you can get ones that can be monitored in software. Then just cludge yourself together a remote interface for it.

alarm system

[austad]

Get a security system. ADT and Brinks suck, I had them before and when I got broken into, no one called or showed up. When I called to ask them why they weren't on the ball, they said they though it was a false alarm, but they didn't even bother to check.

Go with a local company. I'm in Minneapolis and use Sentry Systems, they are cheap, $40 a month. And, you can add a temp sensor that they will monitor for only the price of the sensor ($45 on ebay). They also have water sensors, which I place by my drains in the basement in case the sewer backs up (which it has). They'll call you when one of them throws an alarm. You just give them a list of numbers to try in order.

Re:alarm system

[secret_squirrel_99]

Go with a local company. I'm in Minneapolis and use Sentry Systems, they are cheap, $40 a month

$40.00 a month is cheap? I use a local company which has me patched directly into a panel at the local police dispatch and fire station. I pay $90.00 a year and because there is no third party, I get actual police response when my alarm signals.

Re:alarm system

[HeyLaughingBoy]

Get a security system. ADT and Brinks suck, I had them before and when I got broken into, no one called or showed up. When I called to ask them why they weren't on the ball, they said they though it was a false alarm, but they didn't even bother to check.

Go with a local company. I'm in Minneapolis and

Really? I'm surprised. I moved out of SW Minneapolis recently and I used Brink's ($29.91/mo for 3 doors and an internal motion sensor). I had one false entry alarm probably caused by me taking too long to leave the house, and a smoke alarm caused by a backed up chimney flue. They called the police for the first (after trying the house) and the FD was dispatched for the second before they even tried to call me. The few times I had any interaction with them I thought they were pretty good.

That said. To the OP: there have been a few good suggestions and here's mine: I used to sell RS232 ambient temperature monitoring interfaces. Still have a few lying around, but the price might be more than you want to pay. Originally sold for $112, I can sell you one for $40 with power supply and wall-mount case. Sensor is on a 6' cable. I emphasize one because I know there is at least one more built and tested and if I have to build more the price will go back up.

Re:alarm system

[austad]

Most police departments won't allow that, or they will ignore direct calls from alarm systems. Something like greater than 90% of all alarms are false, and this puts the filtering on the police staff. Most require you to go through a 3rd party.

In fact, I'd rather have it go through a 3rd party as they will track you down by phone when there is an alarm before dispatching police, call you after the fact for fire (which gives them time a short amount of time to cancel the call if it's false), deal with durress passwords, etc... Can you rely on a public employee that's part of a union to go through that much trouble? Probably not.

You probably already have a solution.

[chrisatslashdot]

Got a web cam?

Got a thermometer?

Re:You probably already have a solution.

[mrzaph0d]

this reminds me of this article. it used an image recognition algorithm to determine if the cat had something in her mouth. could you modify that to "read" a digital (or maybe even an analog) thermometer and output the temp to a file?

Use the motherboard's monitoring ability

[kawika]

A lot of motherboards have a two-pin header where you can attach a thermistor. Here's some how-to on it. Instead of sticking the thermistor to the inside of the PC, run it outside the box. Now you have a PC thermometer. There is plenty of free software like Motherboard Monitor that you can use to grab the temperature from within your own program.

Step 1: Define the problem.

[jolshefsky]

The problem is, ultimately, did the furnace fail to run when it's supposed to? So when should the furnace be on? How about when the temperature goes below 50 degrees Fahrenheit.

Ultimately, it would probably be most accurate to AND the following logic states: is the temperature below 50 degrees? Is the furnace off? However, one could assume that the temperature will never get below 55 degrees if the furnace is on, so we're left with a device that can determine when the temperature is below 50 degrees.

Let's see ... how about the cheapest thermostat you can buy with the "turn the furnace on" switch tied to set a pin on the RS232 to a particular state ... like maybe turn the carrier detect "on" if the temperature is low.

Low cost, high reliability, access to data from software is easy. Sounds like a good solution to me.

(By the way, I'm looking for something similar so I can determine the outdoor temperature for something like $20 instead of $200 ... and on a Mac and in AppleScript, just to make it really really difficult.)

PIC + Thermister + Parallel Port

[n1ywb]

Connect Thermister to PIC. Write PIC code to A/D convert the thermister once in a while and dump the output to the parallel port. Write a program that reads the parallel port data and dumps it to a file. Done.

If you want to get really fancy you could try using the serial port or the USB port.

60 ??

[kayen_telva]

we keep the house at 60 all winter. do you actually think 60 is cold ?

Re:60 ??

[Shaleh]

maybe he is married (-: My wife has been complaining non-stop about how low I keep the thermostat. Finally compromised with 64.

Re:60 ??

[raygundan]

Lucky bastard. My compromise ended up at 66. I used to keep the thing set at 59. But hey, it's a small price to pay. :)

Keep it simple and go to the hardware store.

[duffbeer703]

Avoid complex and error-prone geek solutions... buy some pipe wrap insulation and a few electric pipe heating cords.

Pipe cords are like an electric blanket for pipes. They get plugged into a standard wall socket and have a built in thermostat to keep the pipes from freezing. Put these in your bathrooms, kitchen sink and basement and you'll be fine. They run about $10.

Also leave a couple of faucets dripping slightly.

If you are leaving your home for more than a week, ask a friend or neighbor to drop by and check things out.

I've been looking too

[Shaleh]

Just for curiousity. Been wanting to do things like map the garage v. house and the like.

*) the items I have found are quite expensive -- $300+ for even the low end stuff.

or

*) it requires a wire be run all the way from the PC to where you want to monitor. This may or may not be easy depending on the house and whether or not you rent v. own. These are still in the $100+ range.

Well,

[SuiteSisterMary]

http://www.sensatronics.com/TempTrax/
http://www.netbotz.com/products/wall.html

You want a Sensaphone

[netringer]

You don't have to invent the solution when an inexpensive commerical one has been sold for over decade. Get a Sensaphone. It should cost $200 or less.

I've used Sensaphones to monitor remote computer rooms. It has alarm input contacts on it so you can connect water sensors and such. It calls a list of phone numbers when triggered by an alarm or low/high temperature and gives the problem and status to you in a voice announcement.

There are other similar slef-contained alarm dialer solutions

Re:You want a Sensaphone

[netringer]

Specifically the Sensaphone Cottage Sitter model.

Household Climate System

[jaredmauch]

So, this is something very close to what i've been thinking of implementing in my home.

I want to place a temp sensor in each room in my home, and interconnect them so I can get the temp. from each room in the house. This way I can see the disparity and why the room with the TV gets up to 80 degrees or more and other rooms are in the 60's.

I want to build a network of temp sensors (need to be somewhat inexpensive, as i need probally 20 or more of them) and in-line duct fans and "cold air return" blowers as well to help provide more consistent temps in my home.

aside: I want to use this, combined with solar+wind to have 'free' air circulation within my home to continue to lower my utility bills. I've already spec'ed out what I need to do that, check here for some useful worksheets.

Re:Household Climate System

[topham]

I would strongly suggest Dallas Semiconductor's 1-wire products.

It's actuall 1 signal wire, and ground, but you connect multiple devices on the same circuit, they are connected in parallel.

DS18S20 - Temperature range: -40C to +85C. (0 is freezing, and 20 is about average room temperaure) $2.57/each. $2.28/each for 25+, etc

These particular ones can run with parasitic power, but they have many other options, with various temperature ranges, pricing and pinouts.

If you really want to be cool you can buy a TINI unit, (processor board that supports the 1-wire bus and is probably via Java; giving yourself if you desire a web interface to the temperature probes and NOT tie up a PC for it.). I have an older TINI unit, it has a serial port, ethernet and supports 2 1-wire bus' The newer ones should have similar funcionality.

pipe wrap

[Parsec]

They sell it down at the local home improvement store.

http://www.homedepot.com/prel80/HDUS/EN_US/diy_m ai n/pg_diy.jsp?CNTTYPE=PROD_META&CNTKEY=Products_2%2 fHeating+%26+Cooling%2fInsulation&BV_SessionID=@@@ @1075912823.1070991396@@@@&BV_EngineID=ccdkadckdmj fmfjcgelceffdfgidgmk.0&MID=9876

Re:pipe wrap

[Parsec]

Oops, let me put that in a proper URL.

USB based temp sensor board = $35

[malakai]

I googled for 'usb temp sensor' and this was the 6th results
DLP-TEMP 2-Channel Temperature Acquisition Board

As seen in Nuts & Volts Magazine
Monitor and log digital temperature data from 1 or 2 sensors (one DS18B20 sensor included with purchase of board)
USB 1.1 Compliant
12F629 microcontroller can be reprogrammed with user code (requires programmer)
Rev 2 silicon from FTDI
No in-depth knowledge of USB required
Call or email DLP Design for volume pricing

They provide C++ and VB Code examples. Pretty simple stuff, apparently this will show up as a COM port. The VB code is funny, it has all the c++ code in it commented out and you can see their porting thought process.

good luck

A more complete solution

[clintp]

I live in a northern climate, so I understand what you're talking about.

Your neighbors are the *best* solution. A gadget solution would be one that would shut off the water and leave it off in the event of a power failure or freezing temperatures.

It should be overridable, of course. But if the power failed (or the temp dropped), the water would stop flowing in from the meter. This would almost completely eliminate the damage if the pipes did freeze. It's not the burst pipes that's the problem -- it's all the water. The incoming pipe from the meter would be fine -- it's normally installed below the frost line anyway.

An improvement: since this would have to be mounted near the incoming water meter (from the city or well) it could also have a drain capability. Picture a "T" shaped device, meter on the left, house on the right, drain out the bottom. Power goes out, it could close the meter-side and open the drain-side allowing the water in the house pipes to drain out a different path to a floor drain (or a tub).

Re:A more complete solution

[toast0]

you know... if the automated system is just gonna turn off the water when hell breaks loose, why not just turn off the water before you go on your long trip?

(I don't know what would happen to a house if the water was turned off for a week or two... i imagine nothing, so long as you remember to turn off the water heater, and to turn everything back on when you get back)

How about a weather duck?

[Judg3]

Weather duck is a neat little gadget made by ITWatchdogs. It's listed at $179 on their site, and seems like a pretty cool little device.
Monitors Temperature, Humidity, Air Flow, Light Level, Door open/closed (I/O ports) internally plus it has a bunch of external sensors you can hook up to it.
Even says:
"With the supplied software, you can receive e-mail alerts or be paged when temperature or any of the other values is exceeded. View the data on the web. Log in Excel spreadsheets. Add a $40 Web Cam and the software attaches a picture to the web page."

Ever since I've gotten out of IT my desire to play with things in the house has increased - so I've been looking into little gadgets like this.
It might not be a home brewed solution, but for under $200 it's cheap enough for me!
For added protection, pick up the liquid sensor and put it in a low spot on the basement - if a pipe bursts, it'll email you and let you know.

(The usual note: I don't work for them. I just think it's a neat product and I haven't seen anything near it's price range that does the same stuff)

Blue Screen of Frost?

[sharkey]

We had to turn the switch off and on to get it working again.

You're living in the MS House of the Future, today!

Powerware Has An Environmental Monitor

[eric2hill]

Have a look-see. You can get it for less than $100 from CDW.

• Monitors temperature,humidity, and status of two contacts/sensors
• Works with any Powerware UPS with any ConnectUPS (TM) Web/SNMP card
• Can be located up to 20 meters (65.6 feet)from the UPS
• Measures ambient temperatures between 0 and 80 C
• Measures relatively humidity between 10 and 90 percent
• Displays status on Web page,IP phone or PDA,or network man- agement system
• Supports user-defined thresholds for temperature, humidity, and contact closure status
• Supports graceful shutdown of affected equipment
• Auto-sends alarms via email,PCS phone,or pager
• Sends SNMP alarms to network management systems
• Two-year limited warranty, option for enhanced warranty (US and Canada)

It's not exactly what you're looking for but....

[FSK]

I realize this is not the "cool, connects to the internet, cost $30 but takes 4 months to build" solution favored by the /. crowd but the simple solution to your problem is to buy a bunch of Thermwell 12 Ft. Water Pipe Heat Cables then forget that this was ever a problem.

60F?

[Anonymous Coward]

That must have been just awful, you poor, poor dear. Let me get you a steaming cup of tea lest you catch the death of you.

This works great -

[bergeron76]

I use this little beauty:

http://www.quasarelectronics.com/3145data.htm

It's serial, but I'm fairly certain it would work with a USB-Serial converter. Also, it allows you to use up to 4 sensors and you can locate where you'd like (Dallas Semiconductor DS1820 3 wire chips).

They also have linux drivers, sample code, etc.

Wrong...

[jkidd]

You have it all wrong. It's not the frozen pipes you have to worry about, it's the ones thawing that should be your concern.

digitemp

[Anonymous Coward]

http://www.digitemp.com/products.shtml

Uh... have the thermocouple replaced

[ka9dgx]

It sounds like your thermocouple on the pilot light is about to die (it happens to to metal fatigue on a normal basis)... have the furnace serviced. This also gets you an inspection for conditions that could lead to Carbon Monoxide generation. In this case, you're not qualfied, so spend the $ instead of doing it yourself.

--Mike--

The device you are looking for is a housesitter

[glassesmonkey]

either:
(a) put a web cam pointed at a thermometer (duh)
(b) hire someone to check on your house regularly

It's not like it is your single most expensive investment in your life!!
Hey why bother paying someone $10/day to check in on things?! (duh)

Dataq DI-194

[L3WKW4RM]

The DI-194 is a nice and cheap device that they used to give away for free, and offers simple 4-channels of analogue input over RS-232. It uses an intentionally obscure protocol to talk over the serial port, so you'll be needing the Dataq DI-194 Linux driver. I've been trying to contact the author (I'm working on Python bindings for this driver) for a few weeks and had no luck, so don't expect to get help from him.

Why so fancy?

[Gudlyf]

Why would you want to log all that data to a computer that you then need to connect to with a computer to read? If you want inexpensive, reliable and easy to use, try something out of the FreezeAlarm line. I use this model on our computer lab and it works like a champ. This way it calls you when a temperature point is reached, the power goes out, etc. You can also call it yourself and get a temp reading. The solution you're talking about sounds overly complex.

A simple thermometer connecting to joystick port

[Thomas Shaddack]

About half year ago I designed something similar, with a pair of SMT160-30 sensors, a joystick port, some wire, some custom software, and gnuplot. I chose these because of not exactly stellar success I had earlier with an attempt to calibrate a thermistor, and these little babies output temperature as pulse-width modulated TTL signal with duty cycle calibrated against temperature; not really much to screw up there. I could also use more complicated 1-wire Dallas Semiconductors sensors, but they didn't have them in my favorite electronics shop and I wouldn't be able to connect them to input-only port.

Complete documentation is at here, including measurement data and graphs for last 8+ months with exception of few days of downtime.

It's working fine, relax.

[jonadab]

If your house is 60F (did you typo that?), everything is working exactly as it
should. Maybe if the temperature were _less_ than room temperature, you might
start to get concerned, but 60 is the highest you would ever want it to be
(unless you're running a nursing home full of little old ladies who eat like
birds and so get the shivers if the room drops below body temperature). We
set our air conditioner lower than that in the summer.

Use a Hobo Boxcar monitor from Onset

[lobotomy]

This product is $49. http://www.onsetcomp.com/Products/Product_Pages/te mperature_pages/H.temp.html

Here is the description from the web site:

The HOBO Temp logger is a miniature, reusable data logger which continuously measures temperature in remote locations. Start the logger, readout, and plot the data with BoxCar or BoxCar Pro for Windows or BoxCar Pro for Macintosh software.

Features

• Standard temperature range: -20C to +70C
• One year battery life (user replaceable)
• Small size: 2.4" tall x 1.9" wide x 0.8" thick and 1 oz.
• Stores up to 1800 measurements
• Nonvolatile EEPROM memory retains data even when the battery has been removed
• Temperature sensor on 4" wire extends from case for external measurement
• Fifteen minute response time in air (One minute response time with sensor outside of case)
• Operating temperature range (logger) -20C to +70C, noncondensing
• Operating temperature range (sensor) -40C to +120C
• Blinking LED light confirms operation
• Sampling intervals from 0.5 seconds to 9.0 hours
• Optional submersible case rated to 400' depth
• Data readout in less than thirty seconds
• Data exportable to spreadsheet programs (Lotus, Excel, etc.)
• Compliance Certificate available
• NIST-traceable Certification available

here you go

[pmsyyz]

http://dsl.aard.org/temp/

free solution

[Webmoth]

1. Get a used thermostat from a remodeling project. You might even check a local HVAC contractor, they've probably got piles of them.

2. Wire it to a serial or parallel port.

3. Write a daemon that watches for contact closure.

4. Upon contact closure, action of your choice takes place.

just the ticket

[moseswhitecotton]

I use this with kermit/perl/mrtg to monitor temperatures in a server room http://www.weathershop.com/temptrax.htm

Dallas/Maxim 1-wire temperature sensor

[Anonymous Coward]

small sensor - $3 - ds18b20
serial port adapter ~ $15 - dssomethingorother
you can attach as many sensors as you like on any old cable (bell wire!!).
Program the interface in Java/C easy to knock up a servlet interface, jsp