Motion / presence sensor
Motion / presence sensors are used to detect movement or presence of person(s) in the room. The sensor is of the binary type and can have two states:
0 (OK) - no presence detected,
1 (ALARM) - presence detected
Sensitivity
It is possible to set the following parameters for this type of sensor:
Movement detection sensitivity- number of movements detected in a measurement period that are required to mark the period of time with the "1" flag (presence detected). Number of movements is compared against this threshold, if the sensor is in the "no presence detected" state (e.g. "if the number of movements detected in a measurement period is larger than 3, mark it as 1").
No movement detection sensitivity - number of movements detected in a measurement period that are required to mark the period of time with the "0" flag (no presence detected). Number of movements is compared against this threshold, if the sensor is in the "presence detected" state (e.g. "if the number of movements detected in a measurement period is lower than 2, mark it as 0").
Movement detection periods - number of the consecutive measurement periods with "1" flag required to change the sensor state to "presence detected" (e.g. "if the number of the consecutive measurement periods with "1" flag is larger than 1, change the sensor state to "presence detected").
No movement detection periods - number of the consecutive measurement periods with "0" flag required to change the sensor state to "no presence detected" (e.g. "if the number of the consecutive measurement periods with "0" flag is larger than 1, change the sensor state to "presence not detected").
The way the sensor works:
User defines a measurement interval
Sensor counts the number of movements in the measurement period
Sensor checks, if the number of movements in the measurement period is over the sensitivity threshold set
If the number of the movements is over the sensitivity threshold, sensor marks the period of time with "1" flag (movement detected)
If the number of the movements is below the sensitivity threshold, sensor marks the period of time with "0" flag (movement not detected)
Sensor checks, if the number of the consecutive measurement periods with "1" or "0" flag is above or below the consecutive measurement periods threshold
If the number of the consecutive measurement periods with "1" is over the threshold, sensor will set its state to "1" - presence detected
If the number of the consecutive measurement periods with "1" is below the threshold, sensor will not change its state
If the number of the consecutive measurement periods with "0" is over the threshold, sensor will set its state to "0" - presence not detected
If the number of the consecutive measurement periods with "0" is below the threshold, sensor will not change its state
All the settings described above can be set with the mobile application. In the upper right corner settings (three dots in the upper right corner -> Advanced -> “Calibration” -> “Calibration parameters” ->”Select a channel”.
Configuration examples
If the sensor shall be used as a regular movement sensor (change its state, if a movement has been detected), use the following settings:
Movement detection sensitivity = 1
No movement detection sensitivity = 0
Movement detection periods = 1
No movement detection periods = 1
All the other settings are used in case of the presence sensor and allow to filter out short movements, that would result in a false positive detection that a room is occupied (e.g. a person opens and closes a conference room door, would result in changing the sensor state to "presence detected") or false-negative detection that a room is not occupied (e.g. a person sits still in a room for a while, would result in changing the sensor state to "presence not detected"). These settings can be adjusted depending on the specification of the room, in which the sensor is used.
The detection area of the motion sensor is shown in the picture below.
An example of using a motion sensor in an office room with six workstations is shown in the picture below. The device was installed on the wall and covers all the desks in the room.
Efento motion sensor configuration:
Movement detection sensitivity = 10
No movement detection sensitivity = 0
Movement detection periods = 1
No movement detection periods = 2
The five-day measurement results for this configuration are shown in the chart below.
The device detected movement only between 7:00 and 18:00 - office working hours. At other times, no movement was detected.
Reversed logic
Motion sensor normally signals the detection of the motion by high state which results in sending over Bluetooth / NB-IoT displaying “ALARM” status. Enabling this function will reverse the logic and the motion detection sensor will indicate the status “OK”.
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