Next time you are in a club and you see some people waving their mobile phones at each other in the manner of a high five at a distance or even resembling a simplified version of the Haka, you make well wonder what they are up to.
Don't worry. The probably have the latest generation of mobile phones equipped with accelerometers that make use of Bluetooth technology to establish local communications links.

 Bluetooth has of course been around for a long time now, and links can be made between Bluetooth phones that can allow the sending of messages and exchange of information and images without having to using your phone network provider. Due to dangers of what is called Bluejacking, which is gaining unauthorised connections to mobile phones using Bluetooth and hacking them, it is necessary to use Bluetooth securely. This means setting up links between phones using a series of passwords and codes which is fiddly and inconvenient.

Hence the Haka dance with the mobiles. What happens is that a group of friends will agree a routine that involves a number of shakes and gyrations of the phone. These can be as amusing or stylish as you wish. Each movement of the phone produces a code via the accelerometer. For instance this could be fast up, slow down, fast left, slow circle etc. as complicated as you wish to make it. The code is then sent between the phones via Bluetooth. If the codes agree a connection is made and data and images can be exchanged over the Bluetooth link.