Patent ID: 12229611

DETAILED DESCRIPTION

FIG.1shows a first smoke detector1, for use in a fire alarm system.

The smoke detector1comprises a smoke detector controller2. The smoke detector controller2could be any microcontroller or processor suitable for controlling the smoke detector1during normal operation, i.e. after the smoke detector1has been initialised in the fire alarm system.

The smoke detector controller2is configured to operate the smoke detector1during normal operation, for example, detecting an increase in smoke levels, determining that the smoke levels exceed a predetermined threshold value, and communicating to a fire alarm control panel via a network that the smoke levels have exceeded the threshold value.

The smoke detector1also comprises a monitoring module4. The monitoring module4comprises a RFID tag and an antenna14for receiving and transmitting wireless signals.

The RFID tag is a semi-passive RFID tag and comprises a local source of power, such as an internal battery6. The internal battery6provides the RFID tag with power so that it may function when the smoke detector1(and the smoke detector controller2) is not being supplied with power through connection to a power source, such as the power source of the fire alarm system, e.g. a mains power source.

The monitoring module4is configured to determine occurrence of a predetermined event12and to store an indication of the occurrence of the event.

In this embodiment, the monitoring module4is configured to determine if the smoke detector1has been exposed to a temperature above a predetermined temperature threshold. Exposure to high temperatures may internally damage the smoke detector1and modify its sensitivity, thus rendering it unsafe.

The monitoring module4comprises a heat sensor8. The heat sensor is powered by the internal battery6. The heat sensor8is configured to detect an ambient temperature within the proximity of the smoke detector1. The monitoring module4is configured to periodically interrogate the heat sensor8to determine whether the smoke detector1is being exposed to a temperature above a predetermined temperature threshold.

The monitoring module4further comprises a memory10. Responsive to determining that the smoke detector1has been exposed to a temperature exceeding the predetermined threshold, the monitoring module4will store a flag within the memory10as an indication of the occurrence of this event. Optionally, the monitoring module4may record additional information, such as a maximum temperature to which the smoke detector1was exposed.

As discussed above, the monitoring module4comprises an RFID tag. The RFID tag allows an external RFID reader device to interrogate the monitoring module4to determine whether a flag has been stored in the memory10of the monitoring module4to indicate that the smoke detector1has been exposed to a temperature exceeding the predetermined temperature.

Additionally, or alternatively, the smoke detector controller2may be configured to internally communicate with the monitoring module4through a digital interface16. For example, the smoke detector controller2may be capable of interrogating the monitoring module4to determine whether a flag has been stored in the memory10of the monitoring module4to indicate that the smoke detector1has been exposed to a temperature exceeding the predetermined temperature.

A method of monitoring the smoke detector1, while the smoke detector1is not being supplied with power, is now described.

When the smoke detector1is in a state where it is not being supplied with power (e.g. the smoke detector1is stored in a warehouse or is being transported), the smoke detector1may experience a predetermined event12such as exposure to a temperature above a predetermined threshold.

Exposure to a temperature above the predetermined threshold will trigger the heat sensor8. The monitoring module4determines that the smoke detector1has been exposed to excessive temperature, and in response stores an indication of the occurrence of the event in the memory10of the monitoring module4.

The smoke detector1is therefore able to monitor the status of the smoke detector1during a period when it is not being supplied with power, and determine if the smoke detector1has been exposed to an excessive temperature that may have a negative impact on the normal mode of operation of the smoke detector1.

In the illustrated embodiments, the monitoring module4can be interrogated in two ways.

In a first instance, the monitoring module4may receive a RFID read request from a transceiver (interrogator) via the antenna14of the RFID tag. In response to the RFID read request, the monitoring module4is configured to transmit any stored indications to the transceiver. In this way a manufacturer can advantageously check, before delivery to an end user, if a smoke detector1has been exposed to an excessive temperature during a period of storage. The use of an RFID interrogator, which does not require line-of-sight in order to interact with RFID tags like monitoring module4, means that with a sufficiently powerful excitation field multiple smoke detectors1may be checked simultaneously, which can increase the speed and efficiency of the quality control procedure. Similarly, a transceiver may be utilised by the end user to check if the smoke detector1has been exposed to excessive temperature prior to receipt by the end user.

In a second instance, upon commencing initialisation of the smoke detector1(e.g. when the smoke detector1is connected into an alarm system during installation and is supplied with power), the smoke detector controller2starts up and transmits a read request to the monitoring module4to see if an indication of the smoke detector1being exposed to excessive temperature has been stored. If such an indication is returned as a result of the read request, then the smoke detector controller2may notify a user (which may be a maintenance engineer, or the like, tasked with installing the smoke detector1in the fire alarm system) that the smoke detector1has been exposed to excessive temperature and may be internally damaged as a result. The smoke detector controller2notifies the user by activating a notification means (not shown) of the smoke detector1, such as an LED or buzzer.

FIG.2shows a second smoke detector101for use in a fire alarm system.

The second smoke detector101operates in a similar manner to the first smoke detector1described above, but differs in the following aspects. Like elements are numbered with corresponding reference signs, but incremented by 100.

In this embodiment, the monitoring module104is configured to determine if the smoke detector101has been manipulated in a particular manner, and thus comprises a manipulation detection switch108. Unauthorised manipulation of the smoke detector101may cause internal damage and the smoke detector101could become faulty and not suitable for installation in the fire alarm system.

The manipulation switch108is an embedded mechanical switch, which in this embodiment connects the monitoring module104to the internal battery106. When the smoke detector101is manipulated in a particular manner, such as when the housing of the smoke detector101is removed, the switch108connects the monitoring module104to the internal battery106, which is normally disconnected from the monitoring module104in this embodiment. Therefore, upon supply of power from internal battery106, the monitoring module104detects that the smoke detector101has been manipulated and the monitoring module104will store a flag within the memory110as an indication of the occurrence of this event.

A method of monitoring the second smoke detector101, while the smoke detector101is not being supplied with power, is now described.

When the smoke detector101is in a state where it is not being supplied with power (e.g. the smoke detector101is stored in a warehouse or is being transported), the smoke detector101may experience a predetermined event112such as unauthorised tampering with the smoke detector101.

The unauthorised tampering, particularly the removal of the housing of the smoke detector101, will cause the switch108to connect the monitoring module4to the internal battery106. The monitoring module104detects that power from the battery106has been supplied and therefore determines that the housing has been removed. In response, the monitoring module104stores an indication of the occurrence of manipulation in the memory110of the monitoring module104.

As above, the monitoring module104may be interrogated by the smoke detector controller102or by an RFID interrogator.

Whilst two exemplary events are illustrated above, being exposed to excessive temperature or manipulation of the housing, it will be appreciate that other types of events may be detected by similar techniques. For example, shock damage may be detected by a suitable shock sensor, for example including an accelerometer.

Furthermore, the detection techniques used in either of the first and second smoke detectors1,101may be used for detection of the other predetermined event. For example, a mechanical switch could be provided for connecting the battery6to the monitoring module4when the temperature exceeds a predetermined temperature. Likewise, an active sensor could be provided for detecting that the housing of the smoke detector101has been removed.

In a further alternative embodiment a monitoring module4may comprise both a sensor8for detecting excessive temperature and a sensor108for detecting tampering. Then, the monitoring module4may store the indication of the occurrence of either predetermined event12,112. This advantageously allows the controller2or transceiver to quickly identify which particular predetermined event12,112occurred, such that knowledge about the transport or storage conditions of the smoke detector1can be obtained.

Whilst the technique above has been described within the context of a smoke detector, it may be similarly employed in other components used within an alarm system.