GB2294606A

GB2294606A - Television Proximity Detector

Info

Publication number: GB2294606A
Application number: GB9521428A
Authority: GB
Inventors: Benny Bahman Elmi
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-10-19
Filing date: 1995-10-19
Publication date: 1996-05-01
Anticipated expiration: 2015-10-19
Also published as: GB9421114D0; GB2294606B; GB9521428D0

Abstract

A controller is located on top of a TV receiver cabinet and includes: a motion detector 22 responsive to the movement of bodies over a predetermined range in front of the receiver 11, a speaker 23, a store (not shown) of recorded messages, an infrared transmitter 24 for transmitting signals to a receiver 13 to control the television receiver 11 and a sensor coil 25. When the detector 22 senses motion within the predetermined range it energises the store of recorded messages and warns of the dangers of being too close to the screen and that the set will be switched off if the person does not move away. The sensor coil 25 detects when the television receiver is on and activates the controller thus avoiding the need to remember to activate the controller each time the TV is used or to leave it permanently activated. <IMAGE>

Description

ELECTRICAL APPARATUS This invention relates to electrical apparatus in which a secondary electrical device is energised in response to the energisation of a primary electrical device. When a primary electrical device, such as a television set, is energised it is often desired to energise secondary electrical devices and yet it is inconvenient to have such secondary electrical devices wired up to the primary device. On the other hand, it is inconvenient to have the secondary electrical device permanently energised or even to remember to switch on the secondary electrical device when the primary device is switched on.The present invention aims to overcome this problem by providing a secondary electrical device for use in conjunction with a primary electrical device which emits electromagnetic flux on energisation, the secondary electrical device comprising means responsive to electromagnetic flux emanating from the primary electrical device for controlling the energisation of components of one or both of the primary and secondary devices.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a diagram of a television receiver with a controller embodying the invention, and Figure 2 is a logic diagram of the operation of the motion detector apparatus of Figure 1, and Figure 3 is a circuit diagram of the sensor loop control circuit.

A television receiver ii has a room antenna 12 and an infrared receiver 13 for receiving remote control signals. When the receiver is connected to the mains supply, the receiver 13 is energised and when suitable control signals are received it will energise the main part of the receiver 11, including the screen and loudspeaker. This main part of the receiver contains the controlled components of the primary electrical device in this embodiment.

When the main part of the receiver is energised, the receiver is fully operative; when only the receiver 13 is energised, it is in stand-by mode.

A controller 21 is located on top of the t.v. receiver cabinet and includes a motion detector 22 responsive to movement of bodies over a predetermined region or range in front of the receiver 11, a speaker 23, a store (not shown) of recorded messages, an infrared transmitter 24 for transmitting signals to the receiver 13 to control the television receiver 11, and a sensor coil 25. The motion detector 22, speaker 23 and the transmitter 24 are controlled components of the secondary electrical device in this embodiment.

The sensor coil 25 has a current induced by electromagnetic flux emanating from the television receiver 11 in its operative (as distinct from standby) condition. The induced current is processed to close the switch connecting the components 22-24 to the mains supply. The energised motion detector 22 can then detect movement within a predetermined region in front of the receiver.

The predetermined area in which the sensor is responsive to motion is adjustable by a controller 26. The adjustment controller 26 can be calibrated in terms of screen size, or the user can be left to adjust the areas to what he considers to be safe. A minimum approach distance of 3 metres is typical.

If no such motion is detected, the detector 22 continues to be energised while the television set is on but once the television set is no longer on, the controller 21 returns to its standby condition in which the movement detector is de-energised until the next time the television receiver is detected to be on by the coil 25. This is illustrated in the logic diagram of Figure 2.

When the detector 22 senses motion within the predetermined area, it energises the store of pre-recorded messages to play a recorded message, for example in the voice of a parent, warning of the dangers of staying within the predetermined area while the television set is on, and saying that the set will be switched off if the person does not move away. After playing the message, if the detector continues to detect movement in front of the receiver, a timer is started, this message is repeated say three times (or a sequence of messages can be broadcast) and after a predetermined time (say 10 seconds) during which motion continues to be detected in front of the receiver an infrared signal is transmitted from the transmitter 24 to turn off the television receiver.

This combination of motion detections is the motion pattern which causes the main portion of the television to be turned off. If the full pattern of motion is not detected during the timing period, then the timer is reset and the detector continues to scan the predetermined area for another motion pattern in it.

The warning message or messages are stored on a single chip. The user can select different messages as he or she desires, or a sequence of messages can be broadcast. The memory cells are non-volatile, so that no power is required to maintain message storage. The playback device enters stand-by mode automatically after the playback cycle and standby current is typically 0.5 micro-amps.

The output of the sensor coil 25 is a 16KHz waveform. After amplification and integration, it becomes a ramp voltage, changing linearly, and in this form can be recognised by a PIC16C57 data processor which is used to process the data into a form suitable for transmitting a turn-on signal to the receiver 13.

The working heart within the CPU is the Arithmetic/Logic Unit (ALU) and contains one register, the 'W'or working register. The PIC16C57 differs from a number of other microcontrollers in having only one main register for arithmetic and logical operations. The W register is 8 bits wide and holds any data for transfer within the CPU. Also within the CPU core are Data Register files which fall into two categories - those which serve as I/O and control and those acting wholly as RAM. Separate busses are used in microcontroller for memory and data to speed up data throughput and improve software safety. This allows simultaneous access to data and program memory.

The transmission of the control signal from the data processor to the receiver 13 can be by means of a direct electrical connection, but the most convenient form of transmission channel is by infrared radiation. With this arrangement the components 22 - 26 can be independent of the television receiver; they will need some form of power supply, possibly from the mains, but there is no need to intrude into the television receiver to make direct electrical connections. The components receive electromagnetic radiation emanating from the television receiver in its operative state and they transmit control signals to the receiver 13 by infrared radiation. The components can be separately packaged, separately purchased and simply placed on or near the television receiver to assist in its control.

In order to allow the data processor to control the receiver 13, the data processor output has to be suitably encoded so that the receiver 13 recognises a "de-energise the main part of the TV receiver" signal with the appropriate security rating. This is done by a key-pad, provided with suitable circuitry to avoid the effects of contact bounce.

Claims

CLAIMS:

1. A secondary electrical device for use in conjunction with a primary electrical device which emits electromagnetic flux on energisation, the secondary electrical device comprising means responsive to electromagnetic flux emanating from the primary electrical device for controlling the energisation of components of one or both of the primary and secondary devices.

2. A device as claimed in claim 1 wherein a controlled component of the secondary device comprises a motion detector arranged to de-energise a component of the primary device in response to a certain motion pattern.

3. A device as claimed in claim 1 or claim 2 wherein its controlled components comprise a store of recorded messages which can be broadcast in response to said motion detector.

4. A device as claimed in any one of claims 1 to 3 wherein the secondary device comprises an infrared transmitter arranged to perform said deenergisation by transmitting an infrared radiation signal to the primary device.

5. A device as claimed in any one of claims 1 to 4 for use with a primary device which comprises a television receiver.

6. A television control device substantially as herein described with reference to the accompanying drawings.