iHabitat - A home automation, security and monitoring system

The iHabitat system consists of several nodes installed/placed around the house. Each node is capable of serveral functions.
The functionality is catageoried into different groups: 1. Communucation functionality gives a node the ability communicate with other nodes or with the outside world (using the internet / phone line / SMS) 2. Sensor functionality enables a node to measure phyisical world parameters like temprature, power consumption etc. 3. Controller functionality enable a node to control equipment around the house. This can including switching on/off appliances, opening/locking a door. 4. UI functionality enable nodes to interface with the user using physical interface and virtual interface. A physical interface could be a LCD display, keypad, LEDs etc. Virtual interfaces include web / mobile based interfaces. 5. Storage functionality enables node to store and log data. Each node atleast one type of communication functioanlity. All nodes are capabable of communication with each other. Gateway nodes are capable of connection to the outside world over the internet, using the phone line or SMS. Bridge nodes are capabable of converting one type of commuication to another (e.g. WiFi to Zigbee). This page is a first draft describing the overall systems and what is expected out of it.  
Objectives: (1) Intelligence: iHabitat shall be able to take decisions on its own based on its learning from its user behaviour. (2) Easy to deploy and use. (3) Open source (4) Strong focus on communication within the network and to the outside world using the Internet.  
User interface: 1. Web based interface (remote administration and monitoring possible) 2. LCD based touch panels around the house (cost too high, only plain LCD displays for now) 3. Regular wall switches for lighting would still work, no need necessary use the interfaces mentioned above 4. Interactive voice based interface (not a priority right now)
Communucation functionality: 1. ADSL for primary Internet connectivity, distributed across the house over WiFi, repeater to extend range. 2. Mobile packet data services (GPRS/EDGE) as backup internet Internet connectivity 3. Sensors and appliance connectivity over Zigbee (also to consider IP over IEEE 802.14.5 wireless PAN) 4. WiFi to Zigbee bridges for easy access to all appliances from the Internet. 5. Security alerts to be communicated over SMS and voice calls to predefined numbers 6. Some nodes of the system to have Infrared to enable the system to control appliances with IR remote controls.  
Sensor functionality: 1.Human presence detection based on PIR, ultrasonic, infrasonicm, visual sensors 2. Sensor network for indoor/outdoor temperature and electricity usage collection  
Security: 1. CCTV type IP based camera survillance system 2. Intruder alarm based on laser trips and PIR for secondary confirmation.
Storage Functionality: 1. Solid state storage (flash memory) for all logs, records. 2. Critical information also to be updated to the Internet.  
Information updates from the internet 1. View RSS feeds on screens across the home 2. User able to set alerts for events (such as incoming mail)  
Power supply: 1 Electrical mains, some nodes to have UPS backup. 2 Small nodes to run on batteries and if possible on solar cells. 3 Battery  
Time synchronization: 1. From NTP servers on the Internet