Adverse condition detector with diagnostics

An adverse condition detector that records historical data concerning the operation of the detector such that the detector can be interrogated by a technician. The microprocessor of the adverse condition detector monitors for alarm conditions and other important information related to the operation of the detector. Upon identifying an important characteristic of the detector operation, the microprocessor time stamps the information and stores the information within memory of the microprocessor. The detector includes an interface pad that is accessible from the exterior of the detector such that a technician can access the interface pad without removing the detector housing.

BACKGROUND OF THE INVENTION

The present invention generally relates to adverse condition detectors, such as smoke detectors, carbon monoxide detectors and combination units. More specifically, the present invention relates to an adverse condition detector that includes the ability to store historical information regarding the alarms generated based on the adverse condition detected and other information regarding the operation of the detector.

Currently available adverse condition detectors, such as carbon monoxide alarms for residential homes, detect a level of carbon monoxide in the area surrounding the alarm device and operate a transducer, such as an audible horn, to indicate to the home occupant that a hazardous level of carbon monoxide has been detected. Similar detectors are available for the detection of smoke and combination units are available that detect both smoke and carbon monoxide.

In the current available adverse condition detecting devices, the detecting device includes little to no capacity to record historical data as to how the detector is operating. As an example, some currently available carbon monoxide detectors display the maximum carbon monoxide concentration detected. However, the detector cannot be interrogated by field service personnel or at the manufacturing facility after a product recall to determine additional information regarding the operation of the detector. Such additional information may include the carbon monoxide buildup, the number of times the alarm was activated or reset. This information may be useful to a service technician. As an example, if a service technician was able to determine the date and time of all of the generated alarms, the technician could determine whether the alarm generating issues are periodic or alternatively that the carbon monoxide increased very slowly over time.

Therefore, it is an object of the present invention to provide an adverse condition detector that includes the ability to store historical information regarding the operation of the adverse condition detector and provide service technicians the ability to download and analyze this historical data. This data can also be used by the manufacturing company to identify any weak points in the detector design.

SUMMARY OF THE INVENTION

The present invention is an adverse condition detector that records the occurrence of various monitored events such that the occurrence of the monitored events can be retrieved by an external interrogating device. The method of operating the adverse condition detector allows the external interrogating device to retrieve the stored monitored events such that trained technicians and service personnel can determine how the adverse condition detector was operating in the field.

The adverse condition detector includes an enclosed housing that surrounds a microprocessor having an internal clock. The microprocessor is in communication with at least a first adverse condition detection circuit that is operable to detect the presence of an adverse condition, such as the presence of smoke or carbon monoxide. When the adverse condition detection circuit detects the presence of an adverse condition or some other related monitored event, the microprocessor within the housing records the occurrence of the monitored event and a time stamp. The time stamp recorded along with the occurrence of the monitored event relates the time of the monitored event occurrence to the initial start-up of the adverse condition detector. Thus, if the date and time the adverse condition detector was placed into operation is known, the time stamp can be used to relate the recorded event to real time.

The adverse condition detector further includes an interface pad that is coupled to the microprocessor such that the microprocessor can receive information through the interface pad and transmit information to an external interrogating device through the interface pad. In the preferred embodiment of the invention, the interface pad is included within the enclosed housing. Preferably, the enclosed housing includes a series of openings that allow interface pins to extend through the housing and contact the interface pad. The external interrogating device is able to communicate to the microprocessor through the interface pad such that information can be received from the external interrogating device and transmitted back to the interrogation device through the interface pad.

The adverse condition detector is initially placed in a location to be monitored and the internal clock within the microprocessor is activated, such as through the initial application of a power supply. Once the internal clock of the microprocessor has been activated, the adverse condition detector monitors for the occurrence of one of a series of monitored events related to the operaiton of the adverse condition detector.

Once one of the monitored events has been detected, the value of the monitored event is recorded in the microprocessor along with a time stamp. The time stamp recorded along with the occurrence of the monitored event is the value of the internal clock upon the occurrence of the event. The monitored events and time stamps are continuously recorded within the memory of the microprocessor during the lifetime of the detector operation.

If historical data needs to be recovered from the detector, the microprocessor can be interrogated by an external interrogation device. Specifically, interrogating pins from the interrogating device are placed into contact with the interface pad coupled to the microprocessor. The external interrogation device and the microprocessor can communicate to each other through the interface pad, such as with a serial communication protocol. Alternatively, the communication between the microprocessor and the external interrogation device can be completed using wireless communication techniques.

In addition to recording the occurrence of monitored events, the adverse condition detector can include various counters that are incremented each time the monitored event occurs. The value of each of the occurrence counters can be obtained from the detector by the external interrogation device.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIG. 1, thereshown is a block diagram of an adverse condition detector18of the present invention. As described, the adverse condition detector18of the present invention is a combination smoke and CO detector.

The adverse condition detector18includes a central microprocessor22that controls the operation of the adverse condition detector18. In the preferred embodiment of the invention, the microprocessor22is available from Atmel Mega32, although other microprocessors could be utilized while operating within the scope of the present invention. The block diagram ofFIG. 1is shown on an overall schematic scale only, since the actual circuit components for the individual blocks of the diagram are well known to those skilled in the art and form no part of the present invention.

As illustrated inFIG. 1, the adverse condition detector18includes an alarm indicator or transducer24for alerting a user that an adverse condition has been detected. Such an alarm indicator or transducer24could include but is not limited to a horn, a buzzer, siren, flashing lights or any other type of audible or visual indicator that would alert a user of the presence of an adverse condition. In the embodiment of the invention illustrated inFIG. 1, the transducer24comprises a piezoelectric resonant horn, which is a highly efficient device capable of producing an extremely loud (85 dB) alarm when driven by a relatively small drive signal.

The microprocessor22is coupled to the transducer24through a driver26. The driver26may be any suitable circuit or circuit combination that is capable of operably driving the transducer24to generate an alarm signal when the detector detects an adverse condition. The driver26is actuated by an output signal from the microprocessor22.

As illustrated inFIG. 1, an AC power input circuit28is coupled to the line power within the facility. The AC power input circuit28converts the AC power to an approximately 9 volt DC power supply, as indicated by block30and referred to as VCC. The adverse condition detector18includes a green AC LED34that is lit to allow the user to quickly determine that proper AC power is being supplied to the adverse condition detector18.

The adverse condition detector18includes a voltage regulator42that is coupled to the 9 volt VCC30and generates a 3.3 volt supply VDDas available at block44. The voltage supply VDDis applied to the microprocessor22through the input line32, while the power supply VCCoperates many of the detector-based components as is known.

In the embodiment of the invention illustrated inFIG. 1, the adverse condition detector18is a combination smoke and carbon monoxide detector. The detector18includes a carbon monoxide sensor circuit46coupled to the microprocessor22by input line48. In the preferred embodiment of the invention, the CO sensor circuit46includes a carbon monoxide sensor that generates a carbon monoxide signal on input line48. Upon receiving the carbon monoxide signal on line48, the microprocessor22determines when the sensed level of carbon monoxide has exceeded one of many different combinations of concentration and exposure time (time-weighted average) and activates the transducer24through the driver26as well as turning on the carbon monoxide LED50.

In the preferred embodiment of the invention, the microprocessor22generates a carbon monoxide alarm signal to the transducer24that is distinct from the alarm signal generated upon detection of smoke. The specific audible pattern of the carbon monoxide alarm signal is an industry standard and is thus well known to those skilled in the art.

In addition to the carbon monoxide sensor circuit46, the adverse condition detector18includes a smoke sensor52coupled to the microprocessor through a smoke detector ASIC54. The smoke sensor52can be either a photoelectric or ionization smoke sensor that detects the presence of smoke within the area in which the adverse condition detector18is located. In the embodiment of the invention illustrated, the smoke detector ASIC54is available from Allegro as Model No. A5368CA and has been used as a smoke detector ASIC for numerous years.

When the smoke sensor52senses a level of smoke that exceeds a selected value, the smoke detector ASIC54generates a smoke signal along line56that is received within the central microprocessor22. Upon receiving the smoke signal, the microprocessor22generates an alarm signal to the transducer24through the driver26. The alarm signal generated by the microprocessor22has a pattern of alarm pulses followed by quiet periods to create a pulsed alarm signal as is standard in the smoke alarm industry. The details of the generated alarm signal will be discussed in much greater detail below.

As illustrated inFIG. 1, the adverse condition detector18includes a hush circuit58that quiets the alarm being generated by modifying the operation of the smoke detector ASIC54upon activation of the test switch60. If the test switch60is activated during the generation of the alarm signal due to smoke detection by the smoke sensor52, the microprocessor22will output a signal on line62to activate the hush circuit58. The hush circuit58adjusts the smoke detection level within the smoke detector ASIC54for a selected period of time such that the smoke detector ASIC54will moderately change the sensitivity of the alarm-sensing threshold for the hush period. The use of the hush circuit58is well known and is described in U.S. Pat. Nos. 4,792,797 and RE33,920, incorporated herein by reference.

At the same time the microprocessor22generates the smoke alarm signal to the transducer24, the microprocessor22activates LED64and provides a visual indication to a user that the microprocessor22is generating a smoke alarm signal. Thus, the smoke LED64and the carbon monoxide LED50, in addition to the different audible alarm signal patterns, allow the user to determine which type of alarm is being generated by the microprocessor22. The detector18further includes a low-battery LED66.

When the microprocessor22receives the smoke signal on line56, the microprocessor22generates an interconnect signal through the IO port72. In the preferred embodiment of the invention, the interconnect signal is delayed after the beginning of the alarm signal generated to activate the transducer24. However, the interconnect signal could be simultaneously generated with the alarm signal while operating within the scope of the present invention. The IO port72is coupled to the common conduit20(FIG. 1) such that multiple adverse condition detectors18can be joined to each other and sent into an alarm condition upon detection of an adverse condition in any of the adverse condition detectors18.

Referring back toFIG. 1, the adverse condition detector18includes both a digital interconnect interface74and a legacy interconnect interface76such that the microprocessor22can both send and receive two different types of signals through the IO port72. The digital interconnect interface74is utilized with a microprocessor-based adverse condition detector18and allows the microprocessor22to communicate digital information to other adverse condition detectors through the digital interconnect interface74and the IO port72.

As an enhancement to the adverse condition detector18illustrated inFIG. 1, the legacy interconnect interface76allows the microprocessor22to communicate to so-called “legacy alarm” devices. The prior art legacy alarm devices issue a continuous DC voltage along the interconnect common conduit20to any interconnected remote device. In the event that a microprocessor-based detector18is utilized in the same system with a prior art legacy device, the legacy interconnect interface76allows the two devices to communicate over the IO port72.

An oscillator82is connected to the microprocessor22to control the internal clock within the microprocessor22, as is conventional.

During normal operating conditions, the adverse condition detector18includes a push-to-test system60that allows the user to test the operation of the adverse condition detector18. The push-to-test switch60is coupled to the microprocessor22through input line84. When the push-to-test switch60is activated, the voltage VDDis applied to the microprocessor22. Upon receiving the push-to-test switch signal, the microprocessor generates a test signal on line86to the smoke sensor via chamber push-to-test circuit88. The push-to-test signal also generates appropriate signals along line48to test the CO sensor and circuit46.

The chamber push-to-test circuit88modifies the output of the smoke sensor such that the smoke detector ASIC54generates a smoke signal56if the smoke sensor52is operating correctly, as is conventional. If the smoke sensor52is operating correctly, the microprocessor22will receive the smoke signal on line56and generate a smoke alarm signal on line90to the transducer24.

As discussed previously, upon depression of the push-to-test switch60, the transducer24generates an alarm signal. Since the transducer24of the present invention is a piezoelectric horn that generates an extremely loud audible alarm, a need and desire exists for the transducer24to generate a “scaled down” alarm signal that is not as annoying and painful to a user who is near the transducer. In prior art systems, such as those embodied by U.S. Pat. No. 6,348,871, the amplitude of the alarm signal is reduced for at least a portion of the initial period of the alarm signal to prevent the loud alarm signal from being generated near the user's ears. As discussed previously, this type of system has perceived drawbacks in that the transducer24may sound different or unusual when operated at less than the full signal amplitude.

As illustrated inFIG. 1, the adverse condition detector18includes an interface78connected to the microprocessor22by the communication line80. In the embodiment of the invention illustrated inFIG. 2, the interface78is a jumper that allows an external device, such as a PDA or portable PC, to communicate with the microprocessor22using serial communications. The interface78can include interface pins or pads92on the jumper which can be coupled to a communication cable from either a PDA or a portable PC.

As described above and as set forth below, the diagnostic tool, such as a PDA or PC, communicates with the adverse condition detector using a hard wired serial connection. However, it should be understood that other communication protocols such as RS 232, RS 485, USB, Blue Tooth, TCP/IP and IRDA are contemplated as being other types of communication methods between the detector and the diagnostic device.

In accordance with the present invention, the microprocessor22is configured to include operating software that allows the microprocessor to collect historical data regarding operation of the adverse condition detector. It is contemplated that when the adverse condition detector is initially powered up, the microprocessor22will include an internal clock that begins counting. The clock will keep track of the time expired from the initial power-up such that conventional calendar time and date information can be determined based on the time and date the detector was placed into service. The microprocessor22includes internal operating software that time stamps various readings taken from the smoke detector ASIC54and the carbon monoxide sensor circuit46. For example, when the level of carbon monoxide sensed exceeds a threshold level, the microprocessor22records and stores the carbon monoxide level with a time stamp. Likewise, when the smoke detector ASIC54detects a level of smoke above a threshold value, the microprocessor22again stores the time when the detection occurred along with the level of smoke detected. It is contemplated that the microprocessor22could be configured to record and store numerous events that occur within the adverse condition detector. In addition to storing time-stamp information, the microprocessor can be configured to include multiple counters that record the number of times various alarm-specific events occur. Listed below are the various events/counters that are currently contemplated as being monitored within the adverse condition detector of the present invention, although other events and counters are contemplated:

SC01Total number of internal resets since cleared

SC02Total number of external resets since cleared

SC03Total number of Memory Errors fixed

SC04Total number of Memory Errors found

SC05Push Button Counter

SC06Number CO Alarms

SC08Number CO above 70 PPM Minutes

SC0A Number Remote Smoke Events

SC0C Number Faults

Although the above list indicates eleven different detector functions that are monitored and stored in memory, it is contemplated that various other events could be monitored and stored within the microprocessor22. As described, when each of the events occur, the event is time stamped such that the occurrence of the event can be correlated to the initial power up of the adverse condition detector.

Listed below is an example of the data that can be collected from the adverse condition detector of the present invention:CO reading in ppm.% COHbt reading.Smoke reading in % obscuration per foot.VDDreading in VDC.VBATTreading in VDC.Temperature reading in counts.Time reading in seconds.

As described, when each of the events occur, the event is time stamped such that the occurrence of the event can be related back to the initial power up of the adverse condition detector.

In the preferred embodiment of the invention, the microprocessor22will continue to store the various events discussed above, each having a time stamp indicating when the event occurred relative to the time the detector was placed into service. If the detector is operating normally, the detection events will not ever need to be retrieved by either a field service technician or by the manufacturer. However, if the detector malfunctions or alarms due to detected conditions at a higher than expected rate, a field service technician can interrogate the microprocessor22in the field or the entire detector can be returned to the manufacturer for interrogation.

Referring now toFIG. 3, thereshown is the back surface100of the outer housing of a detector18. Preferably, the outer housing is formed from a molded plastic material. The back surface100includes a power receptacle102having a series of pins104that connect to the line power for the building in which the detector18is installed. The back surface100includes a series of mounting tabs106for positioning the detector in the desired location. The detector back surface100further includes a series of pin openings108that extend through the plastic housing that defines the back surface100.

As shown inFIG. 3, the back surface100includes five pin openings108that correspond to the five interface pins92included on the interface pad78shown inFIG. 2. The detector18is configured such that the interface pad78is positioned directly behind the pin openings108such that external pins can be inserted through the pin openings108to contact the interface pads92contained on the interface pad78. Thus, the interface pad78contained within the housing of the smoke detector can be accessed by using a series of pins that extend through the pin openings108. In this manner, the internal microprocessor22can be interrogated without removing the housing of the detector. In addition, it is contemplated that the jumper can also be utilized to reprogram the microprocessor of the detector by using the series of pin openings108.

In the preferred embodiment of the invention, an information label110is applied to the back surface100to provide operating instructions to the user while covering the pin openings108. When the detector needs to be interrogated, the label110can be removed or the interrogation pins can be inserted through the label and into the pin openings108. After the detector has been interrogated, another adhesive label110can be applied to the back surface of the detector.

It is contemplated that the detector will be interrogated by various types of computer equipment, such as a desktop computer, laptop computer, or PDA. Preferably, the communication will take place utilizing a serial interface, although other communication protocols are clearly contemplated as being within the scope of the invention. If wireless communication protocols are utilized, such as Bluetooth or IRDA, the interface pad78and pin openings108can be eliminated.

During the interrogation process, the message sent between the microprocessor of the detector and the interrogating device can have various different types of message formats while operating within the scope of the present invention. Listed below is a contemplated structure for the messages sent between the microprocessor22and the external interrogating device through the interface pad78.

Shown above is the message structure for the information sent from the microprocessor to the external interrogating device through the interface78. The preamble of each message is a field that contains two bytes that indicates the protocol for the message. The command/response field is only one byte in length and allows the message to indicate whether the command is a read command or a write command. The data field can include from 0-64 bytes and allows the processor to communicate the different events and the time at which the events occurred to the external interrogation device. The check sum section provides the ability to check the complete list of the data transferred.

Listed below is a sample of the messages included in the DATA field that, along with the time stamp information, can be sent from the adverse condition detector to the external device, such as a PDA or PC:

As an example, if the technician wishes to request the current CO reading for the detector, the ASCII string $IRCO003B is sent to the microprocessor of the detector. In this interrogation message, the first two characters $I specify that the protocol is based on the SPI port. The third character R signifies the message is a read command. The next two characters CO request that the current CO level be returned by the microprocessor.

The detector will respond with the ASCII string $Ir00CO00XXXXYY. The response from the detector will include the current CO reading in the places marked with “X”. The characters YY are the checksum values.

In addition to reading information from the detector, the communication protocol between the detector and the external interrogation device can also be used to change various operating parameters of the detector, such as the manufacturing flag or other relevant information.

As can be understood by the above description, the ability of the adverse condition detector to store historic information regarding different events that occurred within the detector allows the service technician the ability to diagnose both the detector and its surroundings. This ability allows for better placement of the detector and the ability to diagnose the surrounding area. As an example, in the case of a CO detector, the technician would be able to determine whether fuel burning appliances, such as water heaters, boilers, clothes dryers, furnaces, fireplaces, stoves and other devices were operating improperly in the area surrounding the adverse condition detector. The ability to monitor the timing of the alarm events and the frequency of these occurrences would aid the technician in analyzing the operation of the devices in the immediate area. Further, since smoke and CO detectors signal adverse conditions occurring within the home, the storage of historical data would allow a service technician to determine if an alarm condition occurred when the home was unoccupied and thus no knowledge of the alarm condition was known.