The word automation brings to mind devices that operate with minimal human intervention. In other words, acting or operating in a manner essentially independent of external influence or control. It finds application in controlling industrial equipments, home appliances, computer peripherals and robots. Bluetooth is a promising new wireless technology, which enables portable devices to form short-range wireless ad hoc networks and is based on a frequency hopping physical layer. Bluetooth is a frequency hopping system, which defines multiple channels for communication (each channel defined by a different frequency hopping sequence). A group of devices sharing a common channel is called a piconet. Each piconet has a master unit, which selects a frequency hopping sequence for the piconet and controls the access to the channel. Other participants of the group known as slave units are synchronized to the hopping sequence of the piconet master
Home and office automation using Bluetooth enabled devices have generated sufficient interest in the networking community. Bluetooth based automation offers flexibility, even when the devices actually present far from the master unit. The commands for the automation unit are given through the software module in PC. From PC the command is given to Bluetooth USB adapter. The Bluetooth USB adapter enables the Bluetooth communication and converts the data into airborne signals. The Bluetooth transceiver has a built-in antenna receives the air borne signals and transfer the data to the embedded controller through serial port. The Bluetooth transceivers can be operated in point-to-point, point-to-multipoint and multipoint-to-multipoint architectures.
The embedded microcontroller is programmed to read the data. The embedded controller is the CPU that decides the operation of the automation unit. The embedded controller used here is 89C51 microcontroller. It is a derivative of 8051 microcontroller whose architecture and instruction set are same as 8051 microcontroller with some additional functionality. Since the controller has the inbuilt peripherals it is called as embedded controller. The embedded controller controls the automation unit as per the commands. Bluetooth based systems are developed to manage proper safeguards to prevent unauthorized leakage of information. Synchronizing data between cell phones, laptops, and PDAs; using cell phones as cordless phones when at home; and connecting PDAs to the office LAN are some of the cumbersome things that are possible with Bluetooth