Associating a mobile device with a group

A group controller, comprising:

• a receiver;
• a transmitter;
• storage means;
• and
• at least one processor configured to use said receiver to receive from a mobile device an identifier determined from a light emission, to associate said mobile device with a group of devices on said storage means, said group of devices being associated with said identifier and comprising no mobile devices which are not receiving a light emission with said identifier, to disassociate said mobile device with said group of devices on said storage means when said mobile device is no longer receiving said light emission with said identifier, and to use said transmitter to facilitate communication between said mobile device and at least one further device from said group of devices.

A method of joining a group of devices, comprising the steps of:

• using a light sensor to receive a light emission from a light source;
• determining an identifier from said light emission, said identifier being associated with a group of devices, said group of devices comprising no mobile devices which are not receiving a light emission with said identifier;
• joining said group of devices;
• communicating with at least one further device from said group of devices;
• and
• leaving said group of devices when said light sensor is no longer receiving said light emission with said identifier.

A method of associating a mobile device with a group of devices, comprising the steps of:

• receiving from a mobile device an identifier determined from a light emission;
• associating said mobile device with a group of devices on a storage means, said group of devices being associated with said identifier and comprising mobile devices which are receiving a light emission with said identifier;
• disassociating said mobile device with said group of devices on said storage means when said mobile device is no longer receiving said light emission with said identifier;
• and
• using a transmitter to facilitate communication between said mobile device and at least one further device from said group of devices.