Multi-stage firm alarm device
There is provided a fire alarm device including multiple light sources, a light sensor, a first processor and a second processor. In a standby mode, the first processor identifies whether to wake up the second processor according to a detection result of the light sensor obtained by detecting emission light of one of the multiple light sources. The second processor identifies whether to generate an alarm according to a detection result of the light sensor obtained by detecting emission light of the multiple light sources. The fire alarm device further includes a thermal sensor for providing detected temperature values to the first processor and/or the second processor to perform the identifying procedure.
1. A fire alarm device, comprising:
a first light source, configured to emit light of first wavelength;
a second light source, configured to emit light of second wavelength, which is different from the light of first wavelength;
a light sensor, configured to detect the light of first wavelength and the light of second wavelength, and respectively generate a first detection signal and a second detection signal;
a first processor, configured to identify whether to generate a wakeup signal according to a standby intensity variation of the first detection signal; and
a second processor, configured to identify whether to generate a fire alarm according to a first intensity variation of the first detection signal and a second intensity variation of the second detection signal after being woken up by the wakeup signal,
wherein after the second processor is woken up by the wakeup signal, the first processor is configured to continuously record the first intensity variation of the first detection signal as a reference of identifying whether to generate the wakeup signal next time and a reference for signal calibration.
2. The fire alarm device as claimed in claim 1 , wherein the second light source does not emit light before the first processor generates the wakeup signal.
3. The fire alarm device as claimed in claim 1 , wherein
the first light source is configured to emit the light of first wavelength at a first frequency before the first processor generates the wakeup signal, and
the first light source is configured to emit the light of first wavelength at a second frequency, higher than the first frequency, after the first processor generates the wakeup signal.
4. The fire alarm device as claimed in claim 3 , wherein the second light source is configured to emit the light of second wavelength at the second frequency without at the first frequency.
5. The fire alarm device as claimed in claim 1 , wherein
the first processor is a fixed point processor, and
the second processor is a floating point processor.
6. The fire alarm device as claimed in claim 1 , wherein the first processor is turned off after the second processor is woken up by the wakeup signal.
7. The fire alarm device as claimed in claim 1 , wherein the first processor is configured to identify whether to generate the wakeup signal by comparing a slope of the standby intensity variation of the first detection signal with a historical record.
8. The fire alarm device as claimed in claim 1 , wherein
the first light source is a blue light emitting diode, and
the second light source comprises at least one of a red light emitting diode, a green light emitting diode and a laser diode.
9. The fire alarm device as claimed in claim 1 , wherein
the light sensor is configured to capture the light of first wavelength at a first frame rate before the first processor generates the wakeup signal, and
the light sensor is configured to capture the light of first wavelength and the light of second wavelength at a second frame rate, higher than the first frame rate, after the first processor generates the wakeup signal.
10. A fire alarm device, comprising:
a first light source, configured to emit light of first wavelength;
a second light source, configured to emit light of second wavelength, which is different from the light of first wavelength;
a light sensor, configured to detect the light of first wavelength and the light of second wavelength, and respectively generate a first detection signal and a second detection signal;
a first processor, configured to identify whether to generate a wakeup signal according to a standby intensity variation of the first detection signal;
a second processor, configured to identify whether to generate a fire alarm according to a first intensity variation of the first detection signal and a second intensity variation of the second detection signal after being woken up by the wakeup signal; and
a thermal sensor, configured to generate temperature values, wherein
the temperature values of the thermal sensor are only provided to the first processor for identifying whether to generate the wakeup signal,
the first processor is configured to generate the wakeup signal when a variation slope of the temperature values is larger than a first slope threshold or the standby intensity variation of the first detection signal is larger than a first variation threshold, and
the first processor is configured to generate the wakeup signal when the variation slope of the temperature values is larger than a second slope threshold, smaller than the first slope threshold, and the standby intensity variation of the first detection signal is larger than a second variation threshold, smaller than the first variation threshold.
11. The fire alarm device as claimed in claim 10 , wherein
the thermal sensor is turned on together with the first processor, or
the thermal sensor is turned on after the standby intensity variation of the first detection signal is larger than a third variation threshold, smaller than the second variation threshold.
12. The fire alarm device as claimed in claim 10 , wherein after the wakeup signal is generated, the thermal sensor stops recording the temperature values and the first processor is turned off.
13. The fire alarm device as claimed in claim 10 , wherein after the wakeup signal is generated, the thermal sensor continuously records the temperature values and the first processor continuously records the first intensity variation of the first detection signal as a reference of identifying whether to generate the wakeup signal next time or a reference for signal calibration.
14. The fire alarm device as claimed in claim 10 , wherein
the thermal sensor is turned on together with the first processor to record the temperature values before the wakeup signal is generated.
15. The fire alarm device as claimed in claim 10 , wherein
the thermal sensor is turned on together with the first processor, or turned on by the first processor using another wakeup signal.
16. The fire alarm device as claimed in claim 10 , wherein
the light sensor is configured to capture the light of first wavelength at a first frame rate before the first processor generates the wakeup signal, and
the light sensor is configured to capture the light of first wavelength and the light of second wavelength at a second frame rate, higher than the first frame rate, after the first processor generates the wakeup signal.
17. The fire alarm device as claimed in claim 10 , wherein
the first light source is configured to emit the light of first wavelength at a first frequency before the first processor generates the wakeup signal, and
the first light source is configured to emit the light of first wavelength at a second frequency, higher than the first frequency, after the first processor generates the wakeup signal.
18. A fire alarm device, comprising:
a first light source, configured to emit light of first wavelength;
a second light source, configured to emit light of second wavelength, which is different from the light of first wavelength;
a light sensor, configured to detect the light of first wavelength and the light of second wavelength, and respectively generate a first detection signal and a second detection signal;
a first processor, configured to identify whether to generate a wakeup signal according to a standby intensity variation of the first detection signal; and
a second processor, configured to identify whether to generate a fire alarm according to a first intensity variation of the first detection signal and a second intensity variation of the second detection signal after being woken up by the wakeup signal, wherein
the light sensor is configured to capture the light of first wavelength at a first frame rate before the first processor generates the wakeup signal, and
the light sensor is configured to capture the light of first wavelength and the light of second wavelength at a second frame rate, higher than the first frame rate, after the first processor generates the wakeup signal.