Preferred embodiments of the invention are described below with reference to the following accompanying drawings.
The receiver circuitry 202 is a configured to wirelessly receive an acoustic signal from a smoke detector, such as smoke detector 104, of the smoke detector system 100. The received acoustic signal is provided to the processing circuitry 206 for further processing, which can include for example, demodulation.
The acoustic horn 204 is configured to generate an acoustic alarm. An alarm in the 85 decibel range can be used. Alarms of the acoustic frequencies can be generated as desired. The acoustic horn 204 is controller by the processing circuitry 206.
The processing circuitry 206 is configured to control the operation of the smoke detector 102. The processing circuitry 206 is also configured to detect smoke and generate and detect acoustic signals. In one embodiment, acoustic signals generated by the acoustic horn 204 are modulated using a digital code by turning the acoustic signal “on” and “off”. In another embodiment, the frequency of the acoustic signal can be shifted (e.g., frequency shift keying (FSK)) for a specific period of time in order to modulate the digital code.
In the embodiment where the acoustic signals are turned “on” and off”, a “1” is represented by the acoustic horn 204 being “on” and a “0” is represented by the acoustic horn 204 being “off”. In the embodiment of the FSK a “1” is represented by the acoustic horn 204 operating at one frequency for a fixed period of time and a “0” is represented by the acoustic horn operating at another frequency for a fixed period of time. The digital code, for example, can be made up of a factory set preamble digital code of a predetermined length “X”, or a user-selectable system digital code of length “Y” Followed by a factory set end of transmission code having a predetermined length “Z”.
The digital code can be set by a user by using a switch device 208 having a plurality of switches 209 (e.g. minidip switches) that can be set to be either turned “on” or “off”. The number of switches 209 shown in
The factory set prefixed digital code is used to alert the smoke detector 102 to an incoming digital code string. Each of the smoke detectors 102, 104, 106 and 108 comprised in the smoke detector system 100 is set to the same selectable digital code “Y”. Such selection enables the smoke detectors 102-108 to not interfere with the functioning of smoke detectors that are not comprised in the smoke detector system 100 but otherwise located in close proximity to the smoke detector system 100.
When the smoke detector 102 senses products of combustion (e.g., smoke) or reaches the smoke detector's present threshold of smoke, it activates the acoustic horn (e.g., alarm). As mentioned above, the processing circuitry 206 comprises electronic circuitry to sense smoke. The processing circuitry 206 also includes a storage device configured to store preset data with which measured data is compared. If a value of the measured data exceeds a value (i.e., threshold) of the present data, then the processing circuitry 206 activates the acoustic horn 204 and an alarm is generated. The processing circuitry 206 causes modulation of the alarm generated by the acoustic horn 204. The alarm is modulated in accordance with the digital code set by the plurality of switches 209. The modulated alarm is transmitted via wireless acoustic communication to be received by another smoke detector comprised in the smoke detector system 100 (
Each of the smoke detectors 102-108 are configured to receive the acoustic signals generated by the acoustic horns and to compare the selectable code string “Y” to determine if the code matches the selectable code to which the smoke detector is set. For example, if the smoke detector 104 receives the acoustic signal generated by the acoustic horn 204 of the smoke detector 102, the selectable code string “Y” is compared with the selectable code string that is preset in the smoke detector 104. If a code match is detected, then the smoke detector receiving the code string is forced into the alarm mode and its acoustic horn transmits the digital code to any other smoke detectors that are set to the same detectable digital code string.
The smoke detectors, which are in the alarm mode, remain in such mode until the products of combustion or smoke clears. The receiving circuitry 202 of the smoke detectors in the smoke detector system 100 periodically check for the reception of the selectable code, and if received continues in the alarm mode. If the selectable code is not received by the receiving circuitry 202, the processing circuitry of the respective smoke detectors resets the smoke detectors to a no alarm state if the respective smoke detectors additionally stop detecting the smoke. For example, if the smoke detector 102 detects smoke, it sounds the alarm and thereby sets off alarms of other smoke detectors (e.g. 104. 106. 108) of the smoke detector system 100. Tile smoke detector 102 can be reset if it no longer detects the smoke, while the smoke detectors 104. 106, and 108 can be reset only when the smoke detector 102 is reset (or in the case when one of the smoke detectors 104, 106, and 108 also detect smoke, when that particular detector additionally stops detecting the smoke).
Acoustic signals received by the receiver circuitry 202 are forwarded to the processing circuitry 206 for further processing which can include demodulation.
The smoke detector 102 is configured to wirelessly receive an acoustic signal by the receiver circuitry 202 and transmit an acoustic signal generated by the acoustic horn 204. The processing circuitry 206 is configured to modulate the acoustic signal generated by the acoustic horn 204 as well as demodulate the acoustic signal received by the receiver circuitry 202. It will be appreciated that the smoke detectors (e.g., detectors 102. 104, 106. 108) described above with respect to
At a step 302, the presence or absence of smoke is determined. The method then moves to step 304 if smoke is detected. Otherwise, the method moves to step 310 and no alarm is generated.
At a step 304, an alarm is generated by the acoustic horn (e.g., acoustic horn 204). The method then moves to step 306.
At a step 306, the generated alarm is modulated using a digital code as described above with respect to
At a step 312, the alarm transmitted from smoke detector 102 is received by the smoke detector 104. The method then moves to step 312.
At a step 314, an inquiry is made to determine if the digital code comprised in the received alarm matches the preset code of the smoke detector 104. If true, the method moves to step 316 and the smoke detector 104 sounds its alarm by activating its acoustic horn. Otherwise, the alarm is not activated by the smoke detector 104 as indicated at step 318.
At a step 320, an inquiry is made to determine if the smoke detector 104 continues to receive the alarm from the smoke detector 102. If the step is performed. Otherwise the method moves to step 318 and generation of the alarm is stopped.
A method and apparatus for wirelessly conveying alarm conditions between independent smoke detectors is needed that does not require substantial electronic circuitry and additional power to support such circuitry. In order to establish and maintain wireless communication between independent smoke detectors, each detector would typically need a transmitter and a receiver. By identifying a way to eliminate the need for the transmitter or the receiver in each smoke detector the circuitry needed for communication can be greatly reduced.
In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect.