|HomeNet - A Wireless Network of Household Appliances|
The wireless network upon which the system depends follows an extremely simple and elegant design. There are three element types within the network.
The PC itself runs the program through which the user interacts with the rest of the network. It contains a GUI through which the user can issue commands that get communicated over the network to control the various appliances.
The second element is the master node. It is directly attached to the PC, and communicates through the serial communication port (com port). The master node’s primary job is to forward messages generated on the PC to the rest of the network. It contains a microcontroller that interprets messages sent by the PC and sends them to the other nodes in the network through a hardware transmitter. It also receives acknowledgement messages from other nodes, and forwards them back over the com port to the PC. Beyond these simple functions, the master node does very little.
The final type of element in the network is the receiver node. While we created only one type of receiver node, many more types with different functionality could be created. No matter what the direct functionality of any given receiver node, it always has the same communication functions and follows the same basic protocol. Receiver nodes directly control the home appliances such as the implemented light node. Besides the functionality for controlling their appliance, they are programmed to receive commands sent by the master node, execute the commands, and send some sort of acknowledgement back to the master node. There can obviously be many receiver nodes. Each node has a unique identifying number, and only responds to messages sent to it specifically, ignoring all other messages that it detects over the wireless network.
As the above descriptions imply, the network is organized in a star pattern where the rays of the star may only communicate with the center, and vice versa. The center of the star is the master node, and both the PC and receiver nodes can be said to be rays.