Comparison Xiaomi Aqara E1 Motion Sensor vs Xiaomi Aqara Motion Sensor P1

— Sensitivity adjustment. The ability to change the threshold of the sensor, adjusting it to the specifics of the situation. Such adjustment is mainly used to prevent false positives: for example, so that the outdoor light sensor does not turn on the light, reacting to tree branches swaying in the wind. There are other nuances associated with adjusting the sensitivity; more details about them can be found in special sources.

— Adjustment of illumination. A function mainly used in light sensors. Usually, such devices are equipped with photocells that evaluate the level of ambient light; if it is too light around and there is no need to turn on the lighting, the sensor simply will not respond to “external stimuli”. And adjusting the illumination allows you to adjust the response threshold of the photocell — that is, the level of illumination below which the sensor begins to work for its main purpose.

— Adjustment of the response time. Ability to change the timer on the light sensor. Usually, such sensors, having ceased to detect movement in the field of view, do not turn off the light immediately, but with some delay — this format of operation is considered optimal for a number of reasons. And the adjustment of the response time allows you to set the shutdown time at the request of the user (within certain limits, of course); this can be useful for adjus...ting the sensor to the particular situation. For example, when installing a lamp over the porch of a private house, the front door to this house may be in the dead zone of the sensor; setting the timer allows you to select the shutdown time so that the owner can easily open this door before the light goes out, and the lamp does not waste extra energy.

— Immunity to animals. A function found mainly in motion sensors, including separate models for lighting. The general idea is already clear from the name: this feature allows you to avoid triggering the sensor on cats, dogs and other animals. Such immunity can be useful not only in the presence of domestic “living creatures”, but also in other situations: for example, if neighboring cats can enter the yard served by the sensor. Note that the threshold for this function can be either fixed (for example, “from 20 kg”) or configurable; this point should be clarified separately. And in IR barriers with this function, a different principle is usually used — determining the height of an object. To do this, the device generates two (or more) parallel beams at different heights, and the short-term shading of the lower beam, which is typical for small animals, is not perceived as a trigger.

— Alarm signal. This feature means that the sensor is capable of sounding its own alarm, usually by means of a built-in siren. Such a signal can be very useful in some situations. For example, a siren from a security motion or breakage sensor can attract the attention of witnesses or even the police, significantly complicating the task of an attacker; and the sound from a smoke or gas sensor alerts all people nearby, allowing you to take action to counter an emergency as quickly as possible. Another useful feature of this function is that many sensors with a siren are able to at least partially perform their task even if communication with the control panel is completely lost.

— Protection against opening/separation. Additional protection against attempts to disable the sensor or interfere with its operation: when such attempts are detected, the sensor gives an alarm. Note that the specific features of such protection may be different, depending on the type and specific model of the sensor. Some devices react to a violation of the integrity of the case, others — to the loss of contact with the supporting surface, others — to characteristic shocks, shocks or vibrations that occur when trying to open or tear off the sensor, etc. Such nuances should be clarified separately. However, anyway, this type of protection provides additional security; it does not give an absolute guarantee against interference in the alarm system, however, it greatly complicates such a task.

— Communication jamming notification. A function found in wireless sensors (see "Connection"). When it detects attempts to jam the wireless connection, such a sensor sends a warning to the control panel, and if the connection is completely lost due to jamming, it turns on its own alarm. This makes it much more difficult to interfere with the wireless alarm system.

The angle covered by the sensor horizontally. This is one of the parameters that determines the size of the sensor's field of view, along with the vertical coverage angle (see below).

For wall and similar sensors (see "Installation") that "look" horizontally or almost horizontally, the meaning of this parameter is obvious. But in ceiling models, its value may be different. So, if the coverage angle of 360° is specified for the ceiling sensor, this means that the field of view has the shape of a regular cone, the coverage spot is round, and the width of this cone is determined by the vertical coverage angle. If the viewing angle in such a device is less than 360 °, this means that the cone of the field of view turned out to be “flattened”, the field of view is oval, and the horizontal coverage angle in this case describes the size of the field of view along the long axis. The same applies to models with a combined installation — wall / ceiling.

Anyway, this parameter must be taken into account when choosing a sensor for specific conditions. So, for large rooms with entrances from several sides, omnidirectional sensors are useful, and if there is only one door and there are no other ways of penetration, a narrowly directed one can also come in handy. For a light sensor mounted above the porch of a house, a wide field of view is usually not required; on the contrary, a narrow coverage angle can be an advantage, in particular, it can replace immunity to animals to a certain extent (see "Functions and Capabilities") — in some cases, the sensor can be directed so that it does not see domestic "animals". But corner light sensors, on the contrary, by definition cover a vast area.

A separate case is represented by IR barriers (see "Purpose"). In them, the horizontal coverage angle is the angle by which the IR emitter can be rotated without moving the body of the device. It is indicated by the total covered sector, that is, an angle of 90 ° means the possibility of turning 45 ° in each direction from the central position. Movable emitters are provided for adjusting the system and pointing the beams at the receivers; such a need, usually, arises during installation, because pointing accuracy must be very high, and it is very difficult to achieve it due to the position of the hull alone.

Ambient temperature range in which the sensor is guaranteed to remain operational.

All modern sensors are able to transfer the temperatures typical for residential and office premises without consequences. Therefore, it makes sense to pay attention to this parameter mainly in those cases when the sensor is planned to be used in more unfavorable conditions — for example, on the street, in an unheated room, in a “hot” industrial workshop, etc. At the same time, we emphasize that even for the most "Heat-resistant" models are undesirable exposure to direct sunlight — they can heat the case to temperatures that are much higher than permissible.

The highest relative air humidity at which the sensor can be used.

Many models can easily tolerate short-term (up to several hours) stay in a more humid atmosphere; however, for a complete guarantee, it is still better not to exceed the permissible humidity. As for specific numbers, in residential/office spaces (and similar environments) the relative humidity rarely exceeds 70%. But for outdoor use and rooms with high humidity (swimming pools, laundries, etc.), it is advisable to use sensors designed for a humidity of at least 90%.