I'd like to hook up temperature sensors in my house to remotely monitor pipes during winter. Ideally, I'd like the sensors to upload information via wireless, e.g. in the form of a Tweet or an email.
Does anyone have any experience in this or pointers about how to get started?
I am considering using a Raspberry Pi as the control unit, but haven't made any decisions beyond that. Really just seeking any better informed opinions out there.
There are many ways to do what you want.. but none of them seem very easy as networking remains quite a complex thing to use, wired or wireless.
Obviously you want to just plug in the power and forget about it.
Using the Raspberry PI is most probably a very good idea, Its cheaper version (Model A) about £20, it can run Linux, you can use a WiFi dongle with it. You can remote into it using SSH.. so yes it is actually a very good solution.
Not so long ago
Before the Raspberry the popular choice would most likely be Arduino Ethernet board on it. The costs are slightly higher for this though, There is a Library for use with network available making http communication pretty simple. The drawbacks as of today are obvious, much slower processor, no OS like Linux on it, no SSH, no wireless..(available with other shield + wifi module) and the costs start to pile up.
But today
I am still waiting for my Raspberry to finally arrive and then I can experiment with it. But from my understanding it does have GPIO as on the datasheet page 89 and are available on the PCB it self as double row pin headers. I suspect you can use these to read analog values such as voltages so you could easily connect a temperate sensor like LM335Z. I still have not seen any code on how to do that though but this does seem like the best solution now a days.
But having a few points for monitor can start to cost too much
The nice thing about Arduino still today is that you can buy a small chip like from the tinyAVR that is compatible with Arudino libraries to certain degrees. Using these baby MCU which have built in clocks(fairly accurate now a days)(cost about 1-4usd per chip)with a temp sensor and a cheap as chips 433/800mhz transmitter that sends out temp readings every hour or so. These guys can run on a battery back for 8-16 months. Then using the Raspberry plug in a USB 433/800mhz receiver and just listens to data and the OS level program decides what to do with. Store it in a database somewhere on-line and sends you tweets or text messages via on line gateways in case of emergencies.
This kind of project will require some design time but you could monitor up to 20 places in your home with a total project cost under 100USD ... hmmm. Pretty neat.
Ref:
I have a Radio Thermostat which has a webserver on it that returns information (and accepts controls) in JSON format. So once you have this installed, it would be pretty easy to write an app that runs on a local computer or a dedicated piece of hardware that pings the thermostat for data and then emails/tweets the results. Home Depot USA has Filtrete branded WiFi version of this thermostat that sells for $99.
I have not used one of these yet (or course they are only up for pre order, shipping in June) but the Twine looks like it could be right up your alley. Out of the box ($99) it comes with a thermometer and accelerometer. It can tweet, email and text. It also has the ability to add more sensors. I have been waiting for this as I want to add the magnetic sensors to monitor a door the kids always leave open.
2 years later... ecobee thermostats do this nowadays. A Nest and Honeywell's Lyric probably do, also. If you already have one of these systems, a probe can be run to monitor something critical, hooking to an auxiliary port on the thermostat. It will alert you to changes from a scale you've predetermined.
The OP didn't seem all that hot to trot spending $100 on a toy. I would suggest spending $200 on an upgrade to your house. And then use it as a toy.
