Abstract: A smoke alarm has a base element with a flat mounting surface, a light emitter that is attached to the mounting surface and that is configured to issue an illuminating light, and a light receiver that is attached to the mounting surface next to the light emitter and that is configured to receive a measurement light that results from a back-scattering of the illumination light at a measurement object located in a detection space. A data processing device is coupled to an output of the light receiver and configured to evaluate temporal changes of an output signal issued by the light receiver. Also, there is provided a method for checking the functional capability of the smoke alarm.

Abstract: A device and a method enable a spatially resolved measurement of a temperature inside a spatially linear detection region. The device includes a measuring body having a first electric conductor, a second electric conductor, and an insulating material, which extends between the two electric conductors. The insulating material has a temperature-dependent specific electric resistance. The device further includes a measuring unit, which is connected to the first electric conductor and to the second electric conductor. The measuring unit has a transmitting unit and a receiving unit. The transmitting unit is equipped to apply a time-dependent electric input signal to the two electric conductors. The receiving unit is equipped to detect a time-dependent electric response signal of the measuring body to the input signal. Furthermore, an alarm system is described, which in addition to a central unit has at least one temperature measuring device of the type described above.

Abstract: A smoke alarm is described which comprises a base element (105) with a flat mounting surface, a light transmitter (111) that is attached to the mounting surface and that is configured to issue an illuminating light (111a), and a light receiver (112) that is attached to the mounting surface next to the light transmitter (111) and that is configured to receive a measurement light (112a) which results from a back-scattering of the illumination light (111a) at a measurement object located in a detection space (115). The smoke alarm further comprises a data processing device (135) that is coupled to an output of the light receiver (112) and that is configured to evaluate temporal changes of an output signal issued by the light receiver (112). Also, a method for checking the functional capability of the described smoke alarm (100) is provided.

Abstract: A device for detecting smoke based on the principle of optical scattered light measurements has a light emitting device, configured to issue a temporal succession of light pulses. A first light pulse has a first spectral distribution and a second light pulse has a second spectral distribution that is different from the first spectral distribution. A light receiver receives a first scattered light from the first light pulse and a second scattered light from the second light pulse, and generates a first output signal that is indicative for the first scattered light, and a second output signals that is indicative for the second scattered light. An evaluation unit compares the first output signal with the second output signal. In a preferred embodiment of the device, the light emitter and the light receiver are arranged directly next to one another.

Abstract: A smoke detector, on a base element with a flat installation surface, features a first light transmitter attached to the installation surface for emission of a first illumination light, a first light receiver attached next to the first light transmitter for receiving a first measurement light which results from a backscattering of the first illumination light at a measurement object located in a first detection area. The smoke detector further features a second light transmitter attached to the installation surface for emission of a second object illumination light, a second light receiver attached next to the second light transmitter for receiving a second measurement light which results from a backscattering of the second illumination light at a measurement object located in a second detection area, and a data processing device, which is used for joint evaluation of a first output signal of the first light receiver and of a second output signal of a second light receiver.

Abstract: In a photo-acoustic gas sensor having a measuring cell, a lamp, a photo-diode, a gas-permeable diaphragm and a microphone, a device is included for monitoring the gas-permeable diaphragm and the microphone. The device is operated in an explosion-proof manner. Intentionally, for diagnostic purposes, an artificial pressure modulation is generated in the measuring cell. The pressure modulation is converted by the microphone into electrical monitoring signals which are amplified by an amplifier circuit and assigned to preset ranges by a microprocessor, for determining the functional condition of the diaphragm and the microphone, and of microphone sensitivity. Depending on the range assigned to the monitoring signal, an output signal is generated indicating a fault in the microphone and/or the diaphragm. In the event of long-term drift in microphone sensitivity, a calibration is performed in which gas concentration values are re-calculated and stored in an EEPROM.