The transponder that was implanted in the forearm of Professor Kevin Warwick, on 24th August 1998 consists of a glass capsule containing an electromagnetic coil and a number of silicon chips. It is approximately 23mm long and 3mm in diameter.
When a radio frequency signal is transmitted to the transponder, the coil generates an electric current (an effect discovered by Michael Faraday many years ago). This electric current is used to drive the silicon chip circuitry, which transmits a unique, 64-bit signal. A receiver picking up this signal can be connected in an Intelligent Building network.
By means of a computer, it is able to recognise the unique code and, in the case of an implant, the individual human in question. On picking up the unique, identifying signal, a computer can operate devices, such as doors, lights, heaters or even other computers. Which devices are operated and which are not depends on the requirements for the individual transmitting the signal.
The silicon chip transponder had not, prior to this experiment, been surgically inserted into a human. It was not known what effects it would have, how well it would operate and, importantly, how robust it would be. There was the very real possibility that the transponder might leak or shatter while in the body with catastrophic consequences! The implant in Kevin Warwick's forearm was successfully tested for nine days before being removed.
A follow-up experiment, Project Cyborg 2.0 with a new implant that sends signals back and forth beteween Professor Kevin Warwick's nervous system and a computer began in March 2002.