Whilst pondering over what sensors I could put around the house, I ventured upon the idea of having a ‘sensor box’ per room. This would be based upon something like the Netiom xAP, which would connect various sensors to the house’s IP network. Some of the sensors in each room would be different. Here are some examples of the sensors that would be common to all of the rooms:
- Temperature
- PIR (motion detector)
- Door contact
- Window contacts
- Light
Room specific sensors could be:
Entrance hall:
- Current meter
- Intruder alarm status (triggered/armed)
- Door bell
Kitchen:
- Back door bolt contact
- Oven/hob state
Each of these nodes can then be queried, via the xAP protocol in this case. Temperature could be recorded, although at present our combi-boiler would probably not allow for remote control. Motion detection and door contacts can be used to determine which rooms are occupied, and along with the window sensors could be used as a secondary security system. The light sensors would be used to control the house lights.
Having one single ‘node’ to talk to would do away with having lots of independent sensors that would probably all communicate differently. Thanks to having picture rail throughout most of the house, there won’t be a problem with hiding the wiring. I’m not sure how big the boxes would be, but I dont think they would be massive. I just need to find the money to build a prototype.
Have you looked into the “1-wire” bus system, using only 1 wire for data/parasitic power (plus a ground return) you can hook up many devices for sensing and control, each uniquely addressable. e.g. TO92 style temperature sensor, 2 channel I/O (ideal for light switches), Serial/USB bus interfaces, and more. I’m just looking into HA and have got some 1-wire bits to play with, looks promising.