The overall aim of the project is the development of a single handheld unit that will offer the combination of the conventional computer input devices, the keyboard and the mouse. This handheld unit, the "Key", would fit easily in the palm of the hand and would also have the capability to distinguish the user from other individuals via the manner in which the device is used. Therefore applications exist in the field of personal security access. As a potential security device, the "Key" could hold as much personal information as a smart card and be far less susceptible to illegal use, through user 'signature' detection, or illegal signal reception and decoding, especially with an optical interface system. With the "Key" the signals from the finger force sensors would be analogue so the alphanumeric codes would be extracted by simple threshold detection. The additional information present in the analogue signals, from the sensors under fingers not forcefully pressed to generate characters, will be specific to the users. In this way the generation of text will be similar to handwriting where not only the script but the style will be unique. The "Key" will thus provide a 'signature' that will identify the user. This project will be primarily concerned with the fundamental development of this technology; from the design and build of the prototype handheld unit, development of signal detection electronics, alphanumeric character generation protocols to the production of demonstrator models for computer and security applications. Subsequently further research and development will be necessary prior to any attempt to fully market the "Key" in either of the potential applications.