Smart Home Service Design

In the design of mote-based smart home service, the smart home requirements are break three kinds of service which are home security service, home care service, and home automation service respectively.

a. Home security service:

Home security service which includes two subsystem, entrance guard system and anti-thief system is a significant service in smart home platform. These two home security subsystems are described as below.

Entrance guard subsystem supports a safety gate control. Householder utilizes a reaction mote (Human Mote) to either get in or step out the house. The stranger who doesn’t carry the Human Mote can’t open the gate unless the host opens the door inside for him. The entrance guard system utilizes a mote attached to the gate (Gate Mote) to receive the tag information of Human Mote. If a stranger attempt to utilize a fake mote to get in the house, the Gate Mote checks the error tag information and sends a message back to the Home Server to notify householder and to trigger the alarm noise at the same time. Figure 4.1 shows the architecture of Entrance guard system.

Anti-thief subsystem supports a solution to react the intrusion of thief. To employ infrared rays sensor or reed switch to detect the intrusion is a common approach. Each anti-thief mote (Security Mote) integrated infrared rays or reed-switch circuit is attached on the window lock. When detecting the intrusion, the Security Mote reports intrusion event back to home server and turn on the alarm noise at the same time. It also integrates auto-dial system to notify police and householder and is able to combine with video

Figure 4.1: The architecture of Entrance Guard subsystem

monitor system. When a thief intrudes the house and triggers the sensor through open the window, the system automatically turns on the video monitor system to catch the thief face. Host is able to utilize web-based remote monitor system through the PDA or other handheld devices to monitor house condition. The following figure is the Anti-thief subsystem design architecture. Figure 4.2 shows the architecture of anti-thief system.

Figure 4.2: The architecture of Anti-thief subsystem

b. Home care service:

In recent years, there are many retired people in the world and the elder care com-mercial product becomes more and more popular. Smart home platform is one of these

supplied solutions for elder and defective. If there is a home care service in the smart home platform, the condition of elder or house is able to be monitor. Therefore, the accident can be prevented and the elder and defective can be take care well.

Home care service in the smart home platform can be divided into indoor room lighting subsystem, environment sensing subsystem and fire detecting subsystem. These three home care subsystems are described as below.

Indoor room lighting subsystem is a kind of home care service application for elder and defective. It is an application of location awareness service. As the paper [7] mentioned that the mainly types of localization are physical location, symbolic location, absolute location, and relative location. The concept of symbolic location is employed as the principle to design indoor room lighting subsystem in the smart home platform. It means the location we expressed in natural language way, such as in the kitchen, in living room, in bath room, etc.. The metric to estimate the position in this smart home platform is RSSI (Received Signal Strength Indicator) which is included in the 802.15.4 PHY standard.

The experiment result of the relationship between RSSI and distance is given in Chapter 5. It shows that there is a positive correlative property between RSSI and distance of pair mote. Therefore, a static mote (Room Mote) is attached in each room, and the Human mote receive the signals transmitted by each room in a little period. Human mote select the maximum mote RSSI which is also upper the threshold as the designated Room. This symbolic location approach is combined with automatic indoor light switch. If a host gets in a room and the irradiation is dark enough, the room light is automatically opened. The server can monitor the symbolic position of the Human mote. Figure 4.3 is the design architecture of the indoor room lighting subsystem.

Figure 4.3: The architecture of indoor room lighting subsystem

Another home care service application we developed is environment sensing subsys-tem. There are a lot of service that can be accomplished through sensing the indoor environment, such as temperature, humidity, and luminosity, etc.. If a householder sleeps in a room and home server monitors the variation of temperature via subsystem, the re-lated smart home appliance can be trigger. Figure 4.4 is our environment sensing service design architecture. The Room Mote is responsible to collect the sensing data and for-ward back to the home server, and then the home server perform the reaction according to the receiving data, such as turning on the HAVC.

The other home care service in the smart home platform is smoke sensing subsystem.

The design objective is to prevent fire and prevent injuring if a fire accident occurs.

Figure 4.5 is the design architecture of the smoke sensing service in the smart home platform. There is a smoke sensor integrated with the Room Mote. If the fire accident occurs, the generated smoke triggers the smoke sensor to notify Room Mote to transmit an alarm message to home server. The home server performs urgent tasks, such as notify

Figure 4.4: The architecture of environment sensing subsystem householder via sending the SMS message.

Figure 4.5: The architecture of the smoke sensing subsystem

c. Home automation service:

A home automation service includes the security, cooling, heating, and lighting auto-matically for comfort, energy savings, and convenience. It integrates home appliances into a whole system via data processing technologies. First of all, the home automation system

needs a network to communicate with all controlled home appliances which are able to accept control commands and / or return execution results or internal states. Ex: Net-work Refrigerator, Media Server, etc.. There are some standardized protocols between home appliances and the control system, such as X.10, LonTalk, UPnP, etc.. Finally, context-aware service makes the computer aware of the home environment and provides a comfortable living environment for householder. The auto-dial system is proposed to response the alarm of home security. It is the represent of the context-awareness service.

However, there is a problem of controlling all home appliances in existence. Each appliance have to be control by itself controller or device. The home appliances can be classified by device signal:

1. Infrared rays (IR) appliances: It is common home appliances in being such as DVD, TV, etc.. They are controlled by infrared ray remote controller. The home appliances can learn all the control code of the remote control and then correspond to the relative key.

2. Relay: Commonly, the light or other large current appliances are controlled by relays.

3. RS-232, 422, 485: Such as projector. All the actions and behavior of the appliances is controlled by control code which is transmitted through RS-232 or RS-422 or RS-485.

4. Network: Such as IP Cam.

Briefly, for the sake of developing a whole home automation system, an integrated appliance controller has to be implemented. The controller is able to control either IR-based appliance or relay controlled appliance. However the complicated controller is

not proposed in this smart home platform. For the sake of fulfilling the concept of home automation service design, a control circuit and an emulator is referred. The mote (Automation Mote) attached with the circuit is able to control non-digital home appliance, and the emulator is employed to demonstrate the completion of home automation service.

The emulator includes several kinds of virtual appliance, such as TV, air conditioner, etc..

The design architecture of home automation service is shown in Figure 4.6.

Figure 4.6: The architecture of the home automation subsystem