Communication with a computer by means of a mouse is carried out, for example by pointing an arrow controlled by the mouse at an image or equivalent on the screen and operating the mouse. The image can be an icon which opens a document or program or can be a drawing or text which is to be manipulated. This enables the user to communicate with, and control, the operations of the computer, but does not provide a means for the computer to communicate with the user other than by images on the screen.

We have now invented a device which enables communication from the screen of a computer to control events outside the screen.

According to the invention there is provided an electro-mechanical device adapted to be placed on or adjacent a screen attached to an image generating system, which device incorporates sensors able to detect images on the screen, the device incorporating responding means able to respond to such images and to give an output signal to a user.

The image generating system can be a computer which generates images on a screen or it can be a television receiver, or the system can receive signals from other sources e. g. from a cable or network form an electromagnetic signal etc. and these are converted by the system to images on the screen.

The images on the screen can be in the form of icons, drawings, text etc. and the images can be generated by a pre-programmed sequence generated by the computer, optionally in response to inputs from the user via a keyboard or mouse, or they can be generated via the Internet or computer network.

The output signal can be in the form of a visual image, sound signal or movement of part of the device, or a combination of any or all of these, or it can be by any other signal able to be detected by a user. The device can also be connected to other

equipment so that, when a particular image appears on the screen the device will cause equipment to operate e. g. lights to turn on, recording means to operate etc.

In an embodiment of the invention, the device is removably attached to the screen e. g. by suckers or the like so that it can be placed on the screen when it is to be used and removed when not in use. In another embodiment the device can be wiped or swiped across a screen or held up to the screen.

The sensors in the device can be one or more photosensitive receptors e. g. photodiodes, so that a signal on the screen is converted to electrical signals which are then processed by the device so as to generate a response. The device preferably incorporates a pre-programmed and/or programmable chip or micro-controller. The pre-programmed chip or micro-controller is set to respond in specific ways to images on the screen, so that, when a specific image appears on the screen the device will respond in a pre-determined way. If a programmable chip is also present then a user can load selected programmes on to the chip so that he can choose a specific response.

The device can also be used to decipher encrypted or encoded messages to ensure greater security, in this situation an encrypted or encoded message can be received on the screen e. g. from a network, disc or down the Internet, which can only be decoded by the programme in the device. In these circumstances only a person with the device can gain access to the information. If the device is small and transportable, then a user can keep it with him, so that no one else will be able to have access to the information and the user can use it in conjunction with any computer. This is particularly useful with messages received down the Internet, as a user can log on via any computer and receive secure information with no one else having access to that information. The use of devices, rather than reliance on codes, generally provides greater security and enables sophisticated, essentially unbreakable, encryption to be used. For greater security an encrypted message can be incorporated in a message in such a way that the presence of the encrypted message is apparent but the device of the invention will detect, respond and decipher the message when it is received on a computer screen.

The device can also be used in conjunction with identification means other than numbers or coded words e. g. a sequence of lights which could be emulated or

responded to by a user. This is useful with young children or people with reading difficulties so that the device would flash out a sequence of lights which are emulated or responded to with a mouse so that the user does not have to remember words or number sequences.

The device is also able to be used in conjunction with educational programmes, for example the device will respond in particular physical ways to correct answers to questions and provide much greater stimulus to user compare with presently received audio and visual signals from the computer. The device allows a greater and easier degree of interaction between the user and computer in these circumstances.

The computer can be used as a terminal so that information which is received by the computer and appears on the screen can be received from an external source such as a network, the Internet, radio communication e. g. via a satellite etc. The device can interface with computers, television systems particularly digital television transmissions and any other communication system which utilises a video display unit screen.

The device can optionally incorporate a timing mechanism or clock so that the device can function as a reminder or diary unit. This can be used to alert a user that an action has to be taken e. g. log on to the Internet, turn a television on, go to an appointment etc. The device can be used with other control mechanisms to turn on automatically a recording or other means so that a broadcast etc. is recorded.

When the appropriate chip is incorporated in the device the device can"learn"so that its behaviour is modified by its past experience and activity.

The device can be any shape or configuration and can be in the form of a selected image for advertising and promotion purposes.

It is a feature of the invention that the device acts as a link between the computer and the physical world or"real world"and greatly facilitates the use of the computer by an unskilled user.

The device can be powered by batteries or it can be connected to a mains electricity supply.