Smoke detector

Abstract

A smoke detector and a method of operating a smoke detector are described herein. In some examples, one or more embodiments include a laser emitter configured to emit a laser beam, the laser beam irradiating an object in an area; a light receiver configured to receive light reflected from the irradiated object; and a controller configured to determine an amount of space in the area blocked outside a field of view of the smoke detector by the object based on light reflected from the illuminated object, and provide an indication in response to the determined amount of space being higher than a threshold amount of space.

Description

Technical Field

[0001] This disclosure relates to a smoke detector and a method of operating the smoke detector. Background Technology

[0002] Smoke detectors can be implemented in indoor environments (e.g., buildings) or outdoor environments to detect smoke. For example, a smoke detector can be installed at a point in a room within a building to detect smoke within the room. Smoke detection can minimize risk by acting as a component of a fire control system that alerts users and / or the presence of a fire event in the environment.

[0003] Light detection and ranging (LiDAR) smoke detectors are an example of smoke detectors. LiDAR smoke detectors can utilize optical systems, such as laser beam emitters and light receivers, to detect smoke in the environment. Attached Figure Description

[0004] Figure 1 It is a top view of the area including a smoke detector according to one or more embodiments of this disclosure.

[0005] Figure 2 It is a top view of the area including a smoke detector according to one or more embodiments of this disclosure.

[0006] Figure 3 This is a block diagram of a smoke detector according to one or more embodiments of the present disclosure.

[0007] Figure 4 This is an exemplary method of operation for a smoke detector according to one or more embodiments of the present disclosure. Detailed Implementation

[0008] This document describes a smoke detector and a method of operating the smoke detector. In some examples, one or more embodiments include: a laser emitter configured to emit a laser beam that illuminates an object in a region; a light receiver configured to receive light reflected from the illuminated object; and a controller configured to: determine, based on the light reflected from the illuminated object, an amount of space in the region obstructed from the field of view of the smoke detector by the object, and to provide an indication in response to the determined amount of space being higher than a threshold amount of space.

[0009] Smoke detectors can use a laser beam emitter combined with a light receiver to detect smoke. For example, a smoke detector can use LiDAR (Light Detection and Ranging) technology to detect smoke. When a laser beam is emitted into an indoor environment, it may encounter a substance or material, and the light can be reflected and / or scattered to the light receiver. If no substance or material is present in the laser's path, the light will instead be reflected and / or scattered from the walls of the indoor environment and return to the light receiver. The smoke detector can determine the difference between the received light signal that has been reflected and / or scattered from a wall and the light reflected from another substance or material, because if the received light signal has been reflected and / or scattered from a wall rather than from a substance such as smoke, its intensity will be much greater. Additionally, the light signal that has passed through smoke will attenuate slightly.

[0010] Accordingly, by rotating the laser beam emitter and light receiver of the smoke detector and emitting light pulses from the laser beam emitter, the indoor environment can be scanned to detect smoke. For example, the smoke detector can be positioned in a corner of an area (e.g., a room) and rotated from zero degrees to ninety degrees to scan the smoke throughout the room. By recording the alignment, position, and orientation of the smoke detection system when smoke is detected, the approximate location of the smoke in the room can also be determined.

[0011] However, in some cases, the indoor environment (e.g., a room) may include additional fixed features (e.g., objects), such as pillars, lighting features (e.g., fixtures), signs, and / or ladders, which may reflect and / or scatter light from the emitted laser beam. Such objects may partially obstruct (e.g., block) the smoke detector's field of view and thus may prevent the detector from detecting smoke in the space (e.g., a portion) of the room obstructed by the object. Depending on the size of the object obstructing the detector and / or the position of the object in the room relative to the detector, the amount of space in the room that cannot be detected by the detector may exceed the limits allowed by local applicable smoke detector operating requirements and / or fire codes.

[0012] However, the smoke detector according to this disclosure can identify such obstructions and determine whether such obstructions would result in a breach of applicable smoke detector operating requirements and / or fire codes. Accordingly, during the commissioning (e.g., installation) of the smoke detector, the installer can quickly determine whether the detector installation was successful or whether it needs to be moved to a different location in the room. Furthermore, once the smoke detector has been successfully commissioned and is operational, the detector can continuously identify the presence of any newly introduced obstructions, determine whether they would result in a breach, and provide indication (e.g., notification) of any breach to building management or other appropriate parties.

[0013] Furthermore, for a rotating smoke detector (e.g., a smoke detector with a rotating laser beam emitter and a light receiver) to effectively detect smoke, the laser beam needs to be held over the smoke for a sufficient amount of time (e.g., dwell time) for the detector (e.g., the detector's light receiver) to make an effective measurement. Accordingly, a room scan may not be very fast. However, a full scan of the entire room requires the detector to complete it in the shortest possible time to ensure that smoke present in any part of the room can be detected in a timely manner (e.g., within 60 seconds), as may be required by local smoke detector operation requirements and / or fire codes.

[0014] However, the smoke detector according to this disclosure can reduce (e.g., minimize) its total scanning time while maintaining sufficient dwell time by adjusting its rotation speed based on different parts of the room it scans. For example, the intensity of the light signal received by the light receiver from the smoke plume or the walls of the room, and therefore, the dwell time of the smoke detector is inversely proportional to the square of the distance between the light receiver and the smoke plume or wall. Accordingly, the smoke detector can determine which walls of the room are closer to the detector and which are farther away from the detector, and adjust its rotation speed such that its rotation speed (e.g., scanning) is faster for some parts of the room (where the walls are closer to the detector) and slower for some parts of the room (where the walls are farther away from the detector).

[0015] In the following detailed description, reference is made to the accompanying drawings, which form a part thereof. The drawings illustrate by way of example how one or more embodiments of this disclosure can be practiced.

[0016] These embodiments are described in sufficient detail to enable one or more embodiments of this disclosure to be practiced by a person skilled in the art. It should be understood that other embodiments may be utilized and process, electrical and / or structural changes may be made without departing from the scope of this disclosure.

[0017] It should be understood that elements shown in the various embodiments herein may be added, exchanged, combined, and / or eliminated to provide multiple additional embodiments of this disclosure. The scale and relative dimensions of the elements provided in the accompanying drawings are intended to illustrate embodiments of this disclosure and should not be construed as limiting.

[0018] The figures in this document follow the following numbering convention: one or more first digits correspond to the figure number, while the remaining digits identify elements or parts in the figure. Similar elements or parts between different figures can be identified by using similar digits. For example, 102 can be referenced... Figure 1 The element "02" in the text, and Figure 2 Similar elements in the text can be referenced as 202.

[0019] As used in this article, "one" or "several" can refer to one or more such things, while "multiple" can refer to more than one such thing. For example, "numerous components" can refer to one or more components, while "multiple components" can refer to more than one component.

[0020] Figure 1 This is a top view of area 100 including smoke detector 102 according to one or more embodiments of this disclosure. Smoke detector 102 may be, for example, a light detection and ranging (LiDAR) smoke detector, as will be further described herein. Area 100 may be an area of ​​an indoor environment. For example, area 100 may be a room of a facility (e.g., a building).

[0021] Smoke detector 102 may be part of the facility's fire control system (e.g., a component). As described herein, a fire control system may be any system designed to detect and / or provide notification of a fire event occurring in the facility. For example, a fire control system may include components such as smoke detection devices and / or apparatuses (e.g., detector 102) capable of sensing a fire in the facility, alarms (e.g., loudspeakers, strobe detectors, etc.) capable of providing fire notification to occupants of the facility, fans and / or dampers capable of performing smoke control operations (e.g., pressurization, purging, exhaust, etc.) during a fire, and / or sprinklers capable of providing water to extinguish the fire. A fire control system may also include control units such as physical fire control panels (e.g., boxes) installed in the facility, which users can use to directly control the operation of components of the fire control system. In some embodiments, a fire control system may include non-physical control units or control units located remotely from the facility.

[0022] like Figure 1 As shown, region 100 includes multiple walls: a first (e.g., north) wall 104-1, a second (e.g., east) wall 104-2, a third (e.g., south) wall 104-3, and a fourth (e.g., west) wall 104-4. It should be noted that embodiments of this disclosure are not limited to... Figure 1 The layout or shape of the area 100 shown.

[0023] like Figure 1 As shown, smoke detector 102 (e.g., a laser emitter of smoke detector 102, as will be further described herein) can emit a beam (e.g., a laser beam) 106 across region 100. As used herein, the terms “light” or “beam” can include any type of light beam, such as a laser. These terms can also include light pulses. For example, beam 106 can be a pulsed laser beam (e.g., comprising multiple pulses).

[0024] The smoke detector 102 can rotate the beam 106 (e.g., the rotation mechanism of the smoke detector 102 can rotate the laser emitter of the smoke detector 102, as will be further described herein), such that the beam 106 periodically scans across the region 100 and illuminates different portions of the region 100 (e.g., different portions of the walls of a room), as... Figure 1 As shown by arrow 112. A “scan” of bundle 106 can refer to a rotation of the bundle such that the bundle begins at an initial angular position and ends at an end angular position. As an example, a scan may include the bundle moving from an angle substantially parallel to or through substantially parallel to wall 104-4 (e.g., from an angle of 90 degrees or greater) to or through an angle substantially parallel to wall 104-3 (e.g., to or through an angle of 0 degrees), and a subsequent scan may include the bundle moving from an angle substantially parallel to or through substantially parallel to wall 104-3 back to an angle substantially parallel to or through substantially parallel to wall 104-4.

[0025] like Figure 1 As shown, region 100 may include object 108. Object 108 may be a fixed object, such as a pillar, a lighting feature (e.g., a fixture), a sign, or a ladder, etc. Beam 106 may illuminate object 108, such as... Figure 1 As shown. However, object 108 can partially obstruct (e.g., block) the field of view of smoke detector 102. For example, object 108 can prevent smoke detector 102 from monitoring and detecting. Figure 1 Smoke in space 110 of area 100 shown.

[0026] Smoke detector 102 (e.g., a light receiver of smoke detector 102, as will be further described herein) can receive light reflected from an irradiated object 108 and light reflected from different irradiated portions of region 100 (e.g., irradiated portions of walls 104-1 and 104-2) as a beam 106 scanning across region 100. As used herein, the term "reflection" can be used to refer not only to light but also to light that can be reflected and / or scattered. For example, light can be reflected from a surface at an angle of incidence equal to the angle of reflection. According to embodiments of this disclosure, light incident on a surface or material can also be scattered in multiple directions.

[0027] Based on the light reflected from the illuminated object 108, the smoke detector 102 (e.g., a controller of the smoke detector 102, as will be further described herein) can determine the amount (e.g., size) of the space 110 obstructed from the field of view by the object 108. For example, the smoke detector 102 can measure and / or analyze the intensity of the light reflected from the illuminated object 108 to determine the size of the space 110. The smoke detector 102 can determine the size of the space 110 automatically (e.g., without input from a user) or in response to input from a user (such as the installer of the smoke detector 102).

[0028] For example, smoke detector 102 (e.g., the controller of smoke detector 102) can determine the shape (e.g., contour shape) of region 100 based on light reflected from different illuminated portions of region 100 (e.g., light intensity), and determine the position (e.g., radial coordinates) of object 108 in region 100 based on light reflected from illuminated object 108 (e.g., light intensity). Smoke detector 102 can then determine (e.g., calculate) the size of space 110 based on the determined shape of region 100 and the determined position of object 108 in region 100. Smoke detector 102 can determine the position of object 108 in region 100 based on the alignment of smoke detector 102 when emitting beam 106 (e.g., laser pulse) illuminating object 108 (e.g., the alignment of the detector's laser emitter) and the amount of time it takes for smoke detector 102 to receive light reflected from illuminated object 108 (e.g., the time of flight of the laser pulse illuminating object 108).

[0029] Smoke detector 102 (e.g., the controller of smoke detector 102) can determine whether the amount (e.g., size) of space 110 blocked from view by object 108 exceeds a threshold space amount (e.g., threshold size). The threshold space amount can be predefined or set by the user (e.g., the installer) of smoke detector 102, and can be determined (e.g., defined or set) based on local governing smoke detector operation requirements and / or fire codes of area 100. For example, the threshold space amount could be the maximum amount of unmonitored space allowed in area 100 by local governing smoke detector operation requirements and / or fire codes.

[0030] Smoke detector 102 (e.g., the controller of smoke detector 102) may provide indications (e.g., triggering alarms and / or fault conditions) in response to determining that the size of space 110 is above a threshold space amount. For example, smoke detector 102 may provide indications to the installer of additional devices (such as mobile devices or other computing devices) and / or the manager of the facility via text messages or the Internet or other networks associated with the fire control system of zone 100. In some embodiments, smoke detector 102 may also provide different indications (e.g., to additional devices) in response to determining that the size of space 110 is not above a threshold space amount.

[0031] Although not shown for simplicity and to avoid obscuring the embodiments disclosed herein. Figure 1 However, in some cases, area 100 may include additional objects that could obstruct the field of view of smoke detector 102. For example, the additional object may be a new object introduced into area 100 after smoke detector 102 has been commissioned and / or installed. In this case, beam 106 may illuminate the additional object, and smoke detector 102 may receive light reflected from the illuminated additional object, determine the amount of space in area 100 obstructed from its field of view by the additional object based on the reflected light, and provide an indication in a manner similar to that described for object 108 in response to the determined amount of space exceeding a threshold amount of space.

[0032] Figure 2 This is a top view of region 200, including smoke detector 202 according to one or more embodiments of the present disclosure. Smoke detector 202 and region 200 may, for example, be similar to those previously combined. Figure 1 The smoke detector 102 and zone 200 are described. For example, the smoke detector 202 may be part of a fire control system for a facility that includes zone 200, and zone 200 may include components similar to those in combination. Figure 1 The walls described are 104-1, 104-2, 104-3, 104-4, and multiple walls 204-1, 204-2, 204-3, 204-4.

[0033] Furthermore, the smoke detector 202 can emit a beam 206 across region 200 and rotate the beam 206 such that the beam 206 periodically scans across region 200 and in a manner similar to the previously combined Figure 1 The method of illumination is shown for different portions of the irradiated area 200, as indicated by arrow 212. The smoke detector 202 can be combined in a manner similar to the previously described. Figure 1 The described method receives light reflected from different illuminated portions of region 200 (e.g., illuminated portions of walls 204-4, 204-1, and 204-2) as a beam 206 that scans across region 200.

[0034] Based on the light reflected from different irradiated portions of region 200, smoke detector 202 (e.g., a controller of smoke detector 202) can adjust the rotation speed of beam 206 (e.g., the speed at which the detector's rotation mechanism rotates the detector's laser emitter). For example, smoke detector 202 can measure and / or analyze the intensity of light reflected from different irradiated portions of region 200 to determine the adjustment of the rotation speed of beam 206.

[0035] For example, smoke detector 202 (e.g., a controller for smoke detector 202) can determine the distance from smoke detector 202 to each of the different parts of area 200 (e.g., the illuminated portions of walls 204-4, 204-1, and 204-2) based on the light reflected from the different illuminated portions of area 200 (e.g., the greater the intensity of light reflected from a portion of area 200, the shorter the distance of that portion of area 200 to the detector), and adjust the rotation speed of beam 206 based on these determined distances. For example, smoke detector 202 can adjust the rotation speed of beam 206 such that the amount of time beam 206 illuminates each corresponding different portion of area 200 is proportional to the determined distance of that corresponding portion from smoke detector 202. Accordingly, the rotation speed of beam 206 can pass through those portions of area 200 closer to smoke detector 202 faster and through those portions of area 200 farther from smoke detector 202 slower.

[0036] In this manner (e.g., by adjusting the rotational speed of beam 206), smoke detector 202 can adjust the amount of time (e.g., dwell time) for beam 206 to irradiate each corresponding portion of area 200. For example, smoke detector 202 can adjust the rotational speed of beam 206 through different portions of area 200 such that the beam rotates through each corresponding portion of area 200 at a speed sufficient to detect smoke in that corresponding portion (e.g., slowly enough) but also sufficient to irradiate each portion of area 200 within a specific amount of time (e.g., fast enough to complete a scan of area 200). The specific amount of time can be predefined or set by the user of smoke detector 202 (e.g., the installer) and can be determined (e.g., defined or set) based on the local governing smoke detector operating requirements and / or fire codes of area 200. For example, the specific amount of time can be the maximum amount of time allowed to complete a scan of area 200 by the local governing smoke detector operating requirements and / or fire codes. As an example, the specific amount of time could be 60 seconds.

[0037] Figure 3 This is a block diagram of a smoke detector 302 according to one or more embodiments of the present disclosure. The smoke detector 302 may be, for example, previously combined with... Figure 1 and Figure 2The smoke detectors 102 and / or 202 are described.

[0038] like Figure 3 As shown, the smoke detector 302 may include a laser emitter 322. The laser emitter 322 can be any device, system, or apparatus configured to emit light, such as a laser beam. For example, the laser emitter 322 may emit a laser beam that illuminates an object and / or different portions of the area, as previously described herein. The emitted light may be pulsed, such as a laser pulse. In some embodiments, the laser emitter 322 may be a LiDAR transmitter. In some embodiments, the laser emitter 322 may be a laser diode.

[0039] like Figure 3 As shown, the smoke detector 302 may include a light receiver 324. The light receiver 324 may be or include a sensor, detector, lens, or combination thereof configured to receive light and / or convert light into an instrument-readable form. For example, the light receiver 324 may receive light reflected from an illuminated object in the area and / or from an illuminated portion of the area, as previously described herein. In some embodiments, the light receiver 324 may be a LiDAR receiver or an electro-optic sensor. In some embodiments, the light receiver 324 may include a clock and / or processing resources. The light receiver 324 may be configured to measure the time it takes for a light pulse to travel from the laser emitter 322, be reflected and / or scattered on an object, substance, or material, and return to the light receiver.

[0040] like Figure 3 As shown, the smoke detector 302 may include a rotation mechanism 326 capable of rotating the laser emitter 322. For example, the rotation mechanism 326 may rotate the laser emitter 322 such that the laser beam emitted by the laser emitter 322 periodically scans across an area to illuminate different portions of the area, as previously described herein. The rotation mechanism 326 may be mechanical and / or electrical. It may be configured to rotate the laser emitter 322 at a specific speed and / or within a given range. For example, if the smoke detector 302 is positioned in a corner of an area (e.g., a room), the rotation mechanism 326 may alternately rotate from 0 degrees to 90 degrees and from 90 degrees to 0 degrees from the laser emitter 322. Thus, if the laser emitter 322 periodically emits pulses while being rotated by the rotation mechanism 326, the smoke detector 302 can scan the entire area of ​​smoke. In some embodiments, the rotation mechanism 326 may rotate both the light receiver 324 and the laser emitter 322 together. For example, the rotation mechanism 326 may be a motor-driven rotating platform or table.

[0041] like Figure 3As shown, the smoke detector 302 may include a controller 328 having a processor 330 and a memory 332. The memory 332 may be any type of storage medium accessible by the processor 330 to execute various examples of the present disclosure. For example, the memory 332 may be a non-transitory computer-readable medium having computer-readable instructions (e.g., computer program instructions) stored thereon, which may be executed by the processor 330 to operate the smoke detector 302 according to the present disclosure. That is, the processor 330 may execute executable instructions stored in the memory 332 to operate the smoke detector 302 according to the present disclosure.

[0042] Memory 332 may be volatile or non-volatile memory. Memory 332 may also be removable (e.g., portable) memory or non-removable (e.g., internal) memory. For example, memory may be random access memory (RAM) (e.g., dynamic random access memory (DRAM), impedance random access memory (RRAM), and / or phase-change random access memory (PCRAM)), read-only memory (ROM) (e.g., electrically erasable programmable read-only memory (EEPROM) and / or optical disc read-only memory (CD-ROM)), flash memory, laser disc, digital versatile optical disc (DVD), or other optical disc storage devices, and / or magnetic media such as magnetic tape cassettes, magnetic tape, or disks. Furthermore, memory 332 may be located inside smoke detector 302 or inside another computing resource (e.g., enabling computer-readable instructions to be downloaded via the Internet or another wired or wireless connection).

[0043] Figure 4 This is an exemplary operation method 440 of a smoke detector according to one or more embodiments of the present disclosure. The smoke detector may be, for example, previously combined with... Figure 1 , Figure 2 and Figure 3 The smoke detectors 102, 202, and / or 302 are described. The method can, for example, be derived from previously combined... Figure 3 The described controller 328 runs and / or executes.

[0044] At box 442, method 440 includes rotating a laser emitter of a smoke detector such that a laser beam emitted by the laser emitter illuminates objects and different portions of the area. The laser emitter can be, for example, previously combined Figure 3 The laser emitter 322 is described, and the laser beam emitted by the laser emitter can be, for example, previously combined separately. Figure 1 and Figure 2 The laser beams described are 106 and / or 206. They can be used, for example, in previously combined... Figure 3 The described rotating mechanism 326 rotates the laser emitter. The regions can be, for example, those previously combined separately. Figure 1and Figure 2 The described regions 100 and / or 200 may contain objects that, for example, were previously combined. Figure 1 The described object 108, and different parts of the area may include, for example, different walls of the area, as previously described. Figure 1 and Figure 2 Described.

[0045] At box 444, method 440 includes determining the amount of space in the area blocked from the smoke detector's field of view by the object based on light reflected from the illuminated object. The amount of space blocked from the smoke detector's field of view may correspond to, for example, previously combined... Figure 1 The space 110 is described and can be determined, for example, based on the intensity of light reflected from the illuminated object, as previously combined. Figure 1 Described.

[0046] At box 446, method 440 includes providing an indication in response to a determined amount of space exceeding a threshold amount of space. The threshold amount of space may be defined or set, for example, based on the local jurisdiction of the area's smoke detector operating requirements and / or fire codes, as previously mentioned. Figure 1 The description states that instructions can be provided, for example, to additional devices, as previously described. Figure 1 Described.

[0047] At box 448, method 440 includes adjusting the rotational speed of the laser emitter based on light reflected from different irradiated portions of the region. For example, the rotational speed of the laser emitter can be adjusted based on the intensity of light reflected from different irradiated portions of the region (as previously combined). Figure 2 (as described above), and the speed of the laser emitter of the detector can be adjusted by adjusting the rotating mechanism of the detector (as previously described in this article).

[0048] Although specific embodiments have been illustrated and described herein, those skilled in the art will understand that any arrangement calculated to achieve the same technology may replace the specific embodiments shown. This disclosure is intended to cover any and all modifications or variations of the various embodiments of this disclosure.

[0049] It should be understood that the above description is given in an illustrative rather than restrictive manner. Combinations of the above embodiments, as well as other embodiments not specifically described herein, will be apparent to those skilled in the art upon reading the above description.

[0050] The scope of the various embodiments of this disclosure includes any other application using the structures and methods described above. Therefore, the scope of the various embodiments of this disclosure should be determined with reference to the appended claims and the full scope of their equivalents.

[0051] In the above specific embodiments, for the purpose of simplifying this disclosure, various features are combined in the example embodiments shown in the drawings. This disclosure method should not be construed as reflecting an intention to require more features than expressly recited in each claim.

[0052] Instead, as reflected in the following claims, the subject matter of the invention lies in fewer than all the features of a single disclosed embodiment. Therefore, the following claims are incorporated herein by reference, wherein each claim exists independently as a separate embodiment.

Claims

1. A smoke detector (102, 202, 302), comprising: A laser emitter (322) is configured to emit a laser beam (106, 206) in regions (100, 200). Mechanism (326), configured to rotate the laser emitter (322) such that the laser beam (106, 206) irradiates different portions of the region; A light receiver (324) is configured to receive light reflected from different illuminated portions of the region; and A controller (328) is configured to adjust the speed at which the mechanism (326) rotates the laser emitter (322) based on light reflected from different irradiated portions of the region.

2. The smoke detector of claim 1, wherein the controller is configured to adjust the speed at which the mechanism rotates the laser emitter based on the intensity of light reflected from different irradiated portions of the area.

3. The smoke detector of claim 1, wherein the controller is configured to: The distance of each part of the area from the smoke detector is determined based on the light reflected from different illuminated parts of the area; and The speed at which the mechanism rotates the laser emitter is adjusted based on the distance of each of the different portions of the determined area from the smoke detector.

4. The smoke detector of claim 3, wherein the controller is configured to adjust the speed at which the mechanism rotates the laser emitter such that the amount of time the laser beam irradiates each corresponding different portion of the area is proportional to a predetermined distance of that corresponding portion of the area from the smoke detector.

5. The smoke detector of claim 1, wherein the controller is configured to adjust the amount of time the laser beam irradiates each corresponding different portion of the area by adjusting the speed at which the mechanism rotates the laser emitter.

6. The smoke detector of claim 1, wherein the controller is configured to adjust the speed at which the mechanism rotates the laser emitter to a speed sufficient to detect the speed of smoke in each of the different portions of the area while the laser beam illuminates each of the different portions of the area within a specific amount of time.

7. The smoke detector of claim 1, wherein the controller is configured to determine the shape of the area based on light reflected from different illuminated portions of the area.

8. The smoke detector according to claim 1, wherein different portions of the area include different walls (104, 204) of the area.

9. The smoke detector according to claim 1, wherein the laser emitter is a laser diode.

10. The smoke detector of claim 1, wherein adjusting the speed at which the mechanism rotates the laser emitter comprises increasing or decreasing the speed at which the mechanism rotates the laser emitter.

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