IES990553A2 - An alarm system - Google Patents

Abstract

An alarm system having an armed state and an unarmed state is operated by a keypad (18) which includes record and play buttons (20) and (22), a microphone (26) and a speaker (24) allowing the user to record and play back a short voice message. For security, playback is disabled when the system is armed. <Figure 2>

Description

AN ALARM SYSTEM., ............_ :’· This invention relates to an alarm system, for example for private homes, business premises and. other buildings or sites.

According to the present invention there is provided an alarm system having an armed state and an unarmed state, the system including means for recording and playing back a voice message and means for disabling the playback of a recorded voice message when the system is armed.

The advantage of the invention is that it allows a user to record a voice message that can be played back later by the same user or another authorised user, but only when the system is disarmed. This adds additional security to the system because there are no written messages left around the premises that could be viewed by an intruder, e.g., Gone to shops, back at 6:00pm.

Preferably the alarm system further includes means for also disabling the recording of a voice message when the system is armed.

The alarm system may further include means for providing a visible or audible indication of the presence of a recorded message, the indication being provided only when the system is disarmed.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic diagram of an alarm system embodying the invention; Fig. 2 is an external front view of the keypad of the system of Fig. l; Fig. 3 is a schematic diagram of the internal circuitry of the keypad; Fig. 4 is a block circuit of the audio record and playback circuit of the keypad; Fig. 5 is a schematic diagram illustrating various software routines in the keypad; and Fig. 6 is a flowchart of the audio/buzzer software routine in the keypad.

Referring to Fig. 1, an alarm system includes a central control panel 10, warning devices 12, a communication means 14, a plurality of sensors 16 and a keypad 18.

The control panel 10 is at the heart of the system and controls most of the actions and decisions taken by the system. When the system is armed the warning devices 12 give an audible and/or visual indication that the alarm J system has detected an intruder or a fault condition in the system. The more commonly used warning devices are external bells with integrated strobe light.

The communication means 14 enables communication between the panel and the outside world. The communication means is used to signal alarm events to a central station that in turn contacts the relevant authorities. The communication means may also have the ability to enable remote or local access to the programming of the system and/or other information contained in the system.

The sensors 16 are used to detect an intruder either directly, e.g. by detection of heat from a human body, or indirectly, e.g. by an intruder opening a door.

Sensor technologies are often looped with up to 10 sensors permitted in a loop. When a sensor is activated the loop normally changes state and this causes the control panel to generate an alarm.

The keypad 18 is the main input/output device of the system and is used, for example, to arm/disarm the system, interrogate the system for information relating to alarm activations and for displaying system status information. In the present embodiment the keypad also incorporates a voice message record/playback facility, herein called a voice memopad, that offers convenience and additional security to the users of the system.

Fig. 2 shows the basic elements of the keypad 18. In addition to the usual numeric keys 0-9 and symbol keys # and *, the keypad includes two keys 20, 22 which are labelled R (record) and P (playback) and which are used to operate the voice memopad as will be described. The keypad also includes a loudspeaker 64 (Fig. 4) hidden behind a speaker grille 24 and a microphone 50 (Fig. 4) hidden behind a microphone aperture 26. There are also a number of system status light emitting diodes (LEDs) and a liquid crystal display (LCD) 30.

The internal keypad circuitry, Fig. 3, includes a power supply 32 whose power is derived from the central control panel 10 and a microprocessor-based control unit 34 which is used to implement the various control algorithms in the keypad 18.

A keypad interface 36 scans the keys of the keypad keys to determine when one or more have been pressed, and an LCD interface 38 controls the LCD 30. The latter is used to provide information to the user about the alarm system and, as will be described, also to indicate to the user that the keypad is in the process of recording an audio message. It is also used to indicate that an audio message is waiting to be played to the user.

LED drivers 40 control the LEDs 28 on the keypad to provide system status information. The LEDs are also used to indicate that a message is being recorded by flashing on and off during the record process, as will be described. A communications port 42 allows communications with the control panel 10. This is used by the control panel 10 for polling the keypad for new keys being pressed and other conditions that may exist in the keypad. Typically, the communications port allows a user to arm and disarm the system by keying in a security number, generally a four digit number. It also enables the keypad voice memopad to be under the overall control of the panel to ensure that a keypad will not playback a message when the system is armed.

The control panel 10 determines the armed state.

A buzzer driver 44 is used to generate audible buzzer tones that indicate system status to the user. In particular, in the present embodiment it is used to indicate the end of a record cycle, and also to alert the user to a new audio message when the system is disarmed. An audio record and playback circuit 46 take an audio signal and convert it so that it can be stored for retrieval at a later time. This will be discussed in more detail later. Finally, a speaker driver is used to drive the loudspeaker with audible buzzer tones, derived from the buzzer driver 44, or stored audio, derived from the audio record and playback circuit 46.

Apart from the voice memopad, the alarm system described above is of a generally conventional kind, and its construction and operation is well understood.

Accordingly, the following description will concentrate mainly on the voice memopad function of the system.

The audio record and playback circuit 46 includes a microphone amplifier 52, Fig. 4, to amplify the electrical analog audio signal generated by the microphone 50 corresponding to the speech picked up by the microphone. The audio signal is passed to an automatic gain control (AGC) 54 to control the gain of the amplifier 52 to overcome the large dynamic range of the microphone. The output of the AGC 54 is connected, via the record switch (keypad key) 20 to the input of an ADC/storage block 56. To record an audio message the record switch 20 is closed (keypad key 20 pressed) which causes the analog audio signal to be converted to digital form and stored in solid state memory. The data from the ADC may be compressed.

The output of the ADC/storage block 56 is connected via the playback switch (keypad key) 22 to a digital to analog converter (DAC) 58. The playback switch 22 allows retrieval of the stored digital audio signal which is fed to the DAC 58 where it is converted back to analog form. A filter 60 is used to filter harmonics and other noise introduced into the reconstructed analog audio signal due to sampling and circuit noise.

Finally, a power driver 62 is used to drive the loudspeaker 64 with the reconstructed audio signal.

Fig. 5 is a schematic diagram illustrating various software routines in the keypad which control the keypad circuitry described above.

□ U V The key routine 70 detects a key press and report it to the communications routine 72. In the event that the alarm system is in the unarmed state the record and playback keys 20, 22 are diverted to the audio/buzzer routine 74. The LED routine 76 displays status information from the control panel 10, e.g. a green LED indicates mains status. However, in the event of audio record/playback all status LEDs 28 will blink on/off at 1-second intervals indicating to the user that an audio record or playback is in progress. The LCD routine 78 is normally used to display messages, sent by the control panel 10 via the communications routine 72, on the LCD 30. However the LCD routine 78 can also get messages from the audio/buzzer routine 74. These messages are RECORDING and the AUDIO MESSAGE display messages. As their content suggests, RECORDING is used to indicate that the keypad 18 is recording a voice message and AUDIO MESSAGE is used to indicate that there is an audio message in the keypad waiting to be played. The communications routine 72 enables communication between the control panel 10 and the keypad 18. The control panel polls for information from the keypad (e.g. key presses) using this routine. Also this routine is used to configure the keypad operation, e.g. enable/disable the audio function according to the state, armed or disarmed, of the system. Finally, the audio/buzzer routine 74 controls the operation of the voice memopad in the keypad including the audio record ν «' * and playback circuit 46 and is shown in more detail in Fig. 6.

Referring to Fig. 6, at step 80 the routine tests whether the alarm system is armed, as determined by a status signal from the control panel 10, and the following steps occur only when step 80 determines that the system is disarmed.

Step 82 tests whether the record key 20 is pressed, i.e. whether the user wishes to record a voice message. If so, step 84 of the routine determines the next address in memory to store the message (the user may leave more than one message) and also displays the word RECORDING on the LCD 30, as seen in Fig. 2. Step 84 also flashes the status LEDs 28 at 1-second intervals and mutes the buzzer driver 44. The latter is muted because both the buzzer and the record/playback subsystems use the same output speaker, and the aim is to avoid distortion of the sound the user plays or records.

Next step 86 records the message for as long as the record key 20 is pressed, or until a predetermined maximum record time has been reached. Thus, only messages up to a predetermined duration will be fully recorded. At the end of the record cycle, i.e. when the record key 20 is released or upon' reaching the predetermined maximum record time, step 88 activates the buzzer driver 44 to produce a brief bleep or buzz, for about 1 second. Then, step 90, the message is played back to the user so that he/she can verify what was said. Finally, step 92, the routine sets an internal new audio message flag to indicate that a new message has been recorded and has not yet been played.

Returning to step 82, if the record key 20 has not been pressed, step 94 determines if there is a new message, by examining the new audio message flag set (or not set) at step 92. If there is no message, control reverts to step 80. If there is a message, step 96 activates the buzzer for, say, 10 seconds and displays AUDIO MESSAGE on the LCD 30.

Next, step 98 determines if the playback key 22 has been pressed. If not, control reverts to step 80. If so, step 100 flashes the status LEDs at 1-second intervals, mutes the buzzer driver 44 and clears the new audio message flag to remove the AUDIO MESSAGE display from the LCD 30. Finally, the recorded message is played at step 102. If more than one message has been recorded, then all are played back one after the other, starting with the first. After the message(s) have been played back control reverts to step 80. Although not shown, the keypad control software also removes the AUDIO MESSAGE display from the LCD 30 if the system is rearmed without the message having been played back.

To summarise the operation of the system, when a user wishes to leave a message at the keypad, he/she presses the record button, and then talks in the general direction of the microphone slot. The record button must be kept pressed for the duration of the recording. As the storing means for the recorded message will only have a finite memory, only messages up to a predefined duration will be fully recorded. As the message is recording, the LCD display shows the message RECORDING.

On completion of the record step the user releases the record button. The buzzer on the keypad then bleeps for a brief period, and the message is played back to the user so that he/she can verify what was said. The internal control software then sets a flag that a new message has been recorded and has not yet been played.

The user then arms the system in the usual way and leaves the premises. When he/she or a second user returns to the building, they will have to disarm the system again in the usual way. Once the system has been disarmed, if a message has been recorded, there will be a brief delay, 2-3 seconds say, and the buzzer will bleep for a continuous 10 seconds, indicating that a message has been recorded. Also, the LCD display will display AUDIO MESSAGE. This will display until such time as the audio message has been played back. The buzzer only sounds on the single occasion after the alarm has been disarmed.

In order to play back the recorded message, the user simply presses the play button. He/she does not have to S 6= w if V V keep it depressed, as once play is activated the message(s) will play in its/their entirety. After the message has been played, the AUDIO MESSAGE on the LCD will disappear, and the new message flag in the internal control software will be cleared.

During both the record and play back procedures, the LEDs flash on/off with a period of about 1 second.

When the system is armed, both record and playback facilities are disabled, and the LCD does not display any status information relating to whether a message has been recorded or not.

While the foregoing has described an embodiment with only one keypad, alarm systems commonly comprise several keypads, and in that case the embodiment can be readily extended to allow a message to be recorded at any of these keypads by duplicating the foregoing at each keypad.

In a particular example of such a multi-keypad system, assume there are two keypads, one at the front door and one at the back door. The first user records a message at the front door keypad, arms the alarm and leaves. A second user then returns through the back door, disarms the alarm, but is unaware that a message is awaiting at the front door console. However, once the alarm has been disabled at the back door, the front door console buzzer will then beep, indicating that there is a on message waiting, and its LCD display will display AUDIO MESSAGE.

In another embodiment (not shown) of multi-keypad 5 system, a message recorded at any one keypad is accessible at any other keypad.

The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention.

Claims (5)

1. An alarm system having an armed state and an unarmed state, the system including means for recording and playing back a voice message and means for disabling the playback of a recorded voice message when the system is armed.

2. An alarm system as claimed in claim 1, further including means for also disabling the recording of a voice message when the system is armed.

3. An alarm system as claimed in claim 1 or 2, further including means for providing a visible or audible indication of the presence of a recorded message, the indication being provided only when the system is disarmed.

4. An alarm system as claimed in any preceding claim, wherein the recording and playback means is operated via a keypad which also serves to arm and disarm the system.

5. An alarm system as claimed in claim 1, substantially as described herein with reference to the accompanying drawings.