GB2062987A

GB2062987A - Remote control of a television receiver

Info

Publication number: GB2062987A
Application number: GB8034948A
Authority: GB
Original assignee: Thorn EMI Ltd
Current assignee: Thorn EMI Ltd
Priority date: 1979-11-14
Filing date: 1980-10-30
Publication date: 1981-05-28
Also published as: GB2062987B

Abstract

A hand-held remote controller 1 is battery powered and emits commands in the form of seven bit digital words to a receiving device 2 on the television receiver. A battery voltage sensor 11 senses imminent battery failure and causes the addition of an eighth bit to each command. A decoder 5 in the receiver device 2 then causes a seven segment display 4 to give a battery failure indication F. The decoder 5 may also respond to the eighth bit to make the TV receiver safe via an output channel 3 to prevent loss of control when the battery fails. <IMAGE>

Description

SPECIFICATION Remote control of a television receiver The present invention relates to the remote control of a television receiver.

More particularly, it relates to a remote controller for a television receiver and to a system comprising such a controller and a television receiver.

The remote controller controls the television receiver by the use of control signals which are transmitted to the receiver from a transmitter in the controller. A receiver on the television receiver then receives the control signals and interprets them.

Such remote controllers are battery-operated and suffer from the disadvantages that a sudden battery failure causes loss of control of the receiver. In the past, transmitter devices have been produced with sensing circuits capable of detecting the battery condition built into them, the detected results either being displayed on a meter which formed part of the device or used to trigger a warning indicator, either visible or audible, attached to the transmitter device.

However, a great deal more time is spent watching the television receiver than the control device, so a warning indicator on the transmitter device can easily be overlooked and unexpected battery failure results.

According to one aspect of the invention, there is provided a battery powered hand-held remote con trollerforatelevision receiver including means for selectively emitting control signals for the control of the receiver, and means for sensing imminent battery failure and for causing the control signals to be modified when imminent battery failure is sensed.

According to another aspect of the invention, there is provided a system comprising: a television receiver; and a battery powered hand held, remote controller for the receiver; the controller including means for selectively emitting control signals for the control of the receiver, and means for sensing imminent battery failure and for causing the control signals to be modified when imminent battery failure is sensed; and the receiver including means responsive to the modified signals to display on the receiver an indication of imminent battery failure.

Four a better understanding of the present invention, reference will now be made, by way of example, to the accompanying drawings, in which Figure lisa schematic block diagram of a remote control system of a television receiver, and Figure 2 is a circuit diagram of a battery voltage sensing circuit.

Referring to Figure 1, a hand held remote controller 1 is used to remotely control a television receiver instead of using mechanical or electronic controls mounted on the receiver itself. The controller transmits commands represented by control signals in the form of infra-red radiation to an infra-red receiving device 2 incorporated in the television receiver itself.

The remote controller 1 comprises a keyboard for selecting the commands to be transmitted and an integrated circuit 10 which encodes the commands selected on the keyboard into control signals in a form suitable for transmission by an output circuit 9 which includes infra-red emitting diodes. The commands relate to the choice channel to be viewed on the television receiver and to other controlling actions on the receiver.

The receiving device 2 comprises an output circuit 7 which includes an infra-red sensitive diode to detect the control signals and feed them to a receiver circuit 6 which converts the control signals received by the circuit 7 into a form suitabie for decoding in a decoder 5. The decoder is a micro-computer based circuit which decodes the information into the control signals and relays it to relevant parts of the television receiver. The decoder also controls a seven-segment light emitting diode display 4 mounted on the outside of the television receiver to indicate to a viewer the channel chosen for viewing and for/or other information.

Each control signal has seven bits; a 'start' bit followed by six data bits. The particular command represented by a control signal is determined by the configuration of data bits, which configuration is controlled by the integrated circuit 10.

The remote controller 1 is powered by its own battery and has incorporated in it a voltage-sensing circuit 11 which monitors the condition of the battery. Information from this circuit is added to each of the transmitted infra-red control signals in the form of an eighth bit. The simplest means of coding the battery information is to omit the eighth bit when the battery condition is satisfactory and only transmit an eighth bit when battery failure is imminent.This eighth bit is ignored by the decoder when decoding the size data bits to give the required command but its presence indicates that a warning is necessary and the appearance of the light-emitting diode display 4 is changed, for example to the display shown in Figure 1, so as to warn the viewer that battery failure is imminent and some action is necessary.

The single integrated circuit 10is for example available from Texas Instruments under the designation SN76 831 N20. The integrated circuit controls (in response to the keyboard) the configuration of the start bit and the six data bits in the transmitted control signal, and the condition of one of its pins 12 is controlled by the battery voltage sensor 11 to determine whether or not an extra, eighth, bit is added to the signal to indicate imminent battery failure. If the eighth bit is to be transmitted, the voltage at the pin 12 must drop to 0 volts from its usual level of 9 volts.

In an example of the circuit 11, the low current zener property of the emitter/base junction of a transmitter 13 is used to sense battery voltage. If the battery voltage is greater than approximately 6 volts, current flows through the emitter/base junction of the transistor 13 which causes the transistor 14 to be turned on; this in turn results in transistor 15 being prevented from being turned on so that the pin 12 remains at 9 volts.

If the battery voltage falls below 6 volts, the transistor 13 stops conducting and this results in the transistor 15 being turned on. The voltage at the pin 12 drops to 0 volts and the integrated circuit 10 causes an eighth bit to be added to the transmitted signal, indicating imminentbatteryfailure.

The decoder 5 responds to the eighth bit to produce the failure indication F shown in Figure 1 on the display 4.

The decoder 5 can also be designed or programmed so that the presence of an eighth bit in the infra-red control signal in addition triggers via an output channel 3 the relevant parts of the receiver apparatus causing it to be made safe so that the loss of control dueto battery failure does not do the receiver apparatus any harm.

By extending the operation of the decoder 5 the seven-segment light-emitting diode display 4 mounted on the outside of the television receiver may also give an indication of the command being transmitted when the remote controller is in operation, thus providing a check that the correct command has been transmitted as this is not always immediately clear.

Claims

1. A battery powered hand-held remote controller for a television receiver including means for selectively emitting control signals for the control of the receiver, and means for sensing imminent battery failure and for causing the control signals to be modified when imminent battery failure is sensed.

2. A controller according to claim 1, wherein the control signals represent digital words each having a predetermined number of bits, and the sensing means causes the addition of an extra bit to each word when imminent battery failure is sensed.

3. A controller according to claim 1 or 2, wherein the control signals are emitted in the form of infra-red radiation.

4. A system comprising: a television receiver; and a battery powered, hand held, remote controller for the receiver; the controller including means for selectively emitting control signals for the control of the receiver, and means for sensing imminent battery failure and for causing the control signals to be modified when imminent battery failure is sensed; and the receiver including means responsive to the modified signals to display on the receiver an indication of imminent battery failure.

5. A system according to claim 4, wherein the receiver includes an indicator device for displaying the said indication.

6. A system according to claim 4 or 5 wherein the control signals are emitted in the term of infra-red radiation.

7. A system according to claim 4, 5 or 6, wherein the receiver includes means responsive to the modified signals to renderthe receiver safe.

8. A battery powered, hand held remote controller for a television receiver substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

9. A system comprising a television receiver and a controller according to claim 8.