EE2160/1 - "Make a difference" Stuart Gleave

Research2 > Bluetooth > Bluejacking > Existing apps

Bluetooth:

Bluetooth is a catchy name used to describe a particular wireless radio standard. It provides a way for devices to connect without wires and exchange data with each other across a range anywhere up to 100m. Devices which previously connected via USB or serial ports are likely candidates to have a bluetooth transceiver installed. Computer peripheral cable replacement isn't the only use for bluetooth. Often devices with lower spec than a modern day PC are able to communicate with each other.

There are currently five iterations and three class of bluetooth 1.0, 1.0B, 1.1, 1.2 and 2. Versions 1.0 and 1.0B were somewhat buggy and more experimental. The most common versions of bluetooth in devices in circulation today is 1.1 or 1.2, both with a bitrate of 0.7Mbps. Regardless of the version, all bluetooth devices have a unique address, a MAC address, called BD_ADDR, which can be used to identify specific devices. The 3 classes refer to the strength of the signal produced and are as follows:

Class 3 (1 mW) [rare]: It allows transmission of 10 cm (3.9 in), with a maximum of 1 metre (3.2 ft)
Class 2 (2.5 mW) [most common]: It allows a quoted transmission distance of 10 metres (32 ft)
Class 1 (100 mW) [still readily available]: It has the longest range at up to 100 metres. (320 ft) 1

The power consumption of a bluetooth 1.2 transceiver is considerably less than that of a wifi emitter, as is it's footprint left on a circuitboard. So bluetooth transceivers are smaller, cheaper and more efficient with power than their WiFi equivilant. Bluetooth devices of the present however cannot compete with the bandwidth of a WiFi device.

Version 2.0 of bluetooth is still under development, will be backwards compatible to 1.x., and promises a higher bitrate (2.1Mbps), which will lead to lower power consumption because the device will spend less time transmitting a 20kb file than it's 1.2 predecessor.

There is a new wireless standard on the horizon, zigbee. Designed to go slower, and thus conserve battery life even more it is claimed by some of it's investors "It won't kill Bluetooth, but it might replace it"2. But due to it's newness, low bandwidth (250kbps) and size i couldn't use it for my project, I need to use something already well established.

My research into bluetooth indicates that people are already talking to each other, albeit slightly one way at time in the form of something called bluejacking. Bluejacking is “the sending of unsolicited messages over bluetooth to Bluetooth-enabled devices such as mobile phones, PDAs or Laptop Computers”3 , and is the topic of my next section of research.