Some notes on my temp sensor network at home. This is just some musings on how I made my network- it isn't by any means the only way to do it! If its not understandable let me know and I'll try to explain a bit more- I've tried to keep it at a fairly high level but I can go into more detail on things if required.
1-wire is a protocol by Maxim utilising various sensors such as temperature and humidity.
- I use DS18B20 temperature sensors in either TO92 form, or waterproof ones that come complete with cables- depending if they are internal of external.
- humidity sensors- http://www.sheepwalkelectronics.co.uk/product_info.php?cPath=23&products_id=55
Some notes on building a network: https://www.maximintegrated.com/en/app-notes/index.mvp/id/148
I use cat5 cable for my network, using this wiring diagram: http://www.sheepwalkelectronics.co.uk/wiring_info.php
I connect them by terminating the cat5 cable as usual with rj45 plugs and using splitters to plug in the sensor, and to continue the wire.
- these are super cheap and about 50% of them actually work, they're rather jippy.
- About 80% of these splitters work, but they cost a lot more.
I also use these splitters from SheepWalk Electronics (UK) for 'hubs' where I have many sensors terminating- just out of laziness: http://www.sheepwalkelectronics.co.uk/product_info.php?cPath=23&products_id=64
I'm sure similar products exist in other countries.
So take your pick according to how patient you are.
If outside then the splitters go inside IP68 junction boxes, with cable glands to keep out moisture. Outside I try and protect the cable- either bury it or encase in old garden hose or similar (else you'll be really annoyed when you accidentally cut through it with a hedge trimmer). Indoors the cblaes tend to be under floorboards or embedded in walls.
Some notes on soldering the sensors: http://oozamaflips.net/index.php?month=6&year=2014
The base unit: I use a raspberry pi. The most common 1 wire interface is a DS9094R usb interface, which I started with. As I added more sensors I started getting conflicts on the network so switched to a multi-bus i2c interface: http://www.sheepwalkelectronics.co.uk/product_info.php?cPath=22&products_id=33
On the pi I use the raspbian OS, and install the owfs software to communicate with the sensors. It has a server interface whereby you can check what sensors can be seen and their values and things.
I run a python script every 10 minutes that records the temp/humidity values to a database. And have a webpage acessible in my house where you can view the current, min and max temps. It also does graphs over various time periods and various other things.
Why do I do this? Why not, I like playing with electronics. I also have a weather station I built, pi CCTV cameras.. why would I not want to monitor temperatures in my house (and garden, and greenhouse, and pond, and chicken coop.. and compost bin...)
Do set up your base unit and a few sensors and check it all works! Then add sensors one at a time. Once you have 30 sensors or so on the same bus you start to get conflicts, not all the sensors play nicely with each other. If your nice network vanishes when you add a certain sensor or splitter- replace that with a different one- the first sensor will likely work elsewhere.