Bluetooth Smart is a wireless technology designed for innovative applications in the health, fitness, beacons, home security and entertainment industries. The technology makes use of electronic tags to facilitate automatic wireless identification, with a device enabled for Smart Bluetooth. We are trying to solve the problem of attendance monitoring using a Bluetooth Smart based system in this document. This Bluetooth Smart Student Attendance application improves the time taken during manual attendance and human errors and provides administrators with statistics of attendance scores for use in other administrative decisions.
The Bluetooth network transmits data through low-power radio waves. It communicates at a frequency of 2.45 GHz (actually between 2,402 GHz and 2,480 GHz, to be exact). This frequency band has been canceled by an international agreement for the use of industrial, scientific and medical devices (ISM). A number of devices you can use already take advantage of this same radio frequency band. Baby monitors, garage door openers and the new generation of cordless phones make use of frequencies in the ISM band. Ensuring that Bluetooth and these other devices do not interfere with each other has been a crucial part of the design process. One of the ways that Bluetooth devices avoid interfering with other systems is by sending very weak signals of approximately 1 milliwatt.
In comparison, the most powerful cell phones can transmit a signal of 3 watts. Low power limits the range of a Bluetooth device to about 10 meters (32 feet), reducing the chances of interference between your computer system and your phone or portable television. Even with low power, Bluetooth does not require line of sight between communication devices. The walls of your home will not stop a Bluetooth signal, making the standard useful for controlling multiple devices in different rooms.
Bluetooth can connect up to eight devices simultaneously. With all those devices within the same radius of 10 meters (32 feet), you might think they interfere with each other, but it is unlikely. Bluetooth uses a technique called spread spectrum frequency hopping which makes it strange that more than one device is transmitting on the same frequency at the same time. In this technique, a device will use 79 individual frequencies, chosen at random within a designated range, changing from one to another on a regular basis. In the case of Bluetooth, the transmitters change frequencies 1,600 times every second, which means that more devices can make full use of a limited portion of the radio spectrum.
Since each Bluetooth transmitter uses spread spectrum transmissions automatically, it is unlikely that two transmitters are on the same frequency at the same time. The same technique minimizes the risk of Bluetooth handsets or baby monitors interrupting Bluetooth devices, as any interference on a given frequency will last only a fraction of a second.
It can be understood in the following video: