False triggering is a common problem with home body sensors (e.g. infrared PIR, millimeter wave radar) - lights turn on automatically when no one is there, or no response when they should be triggered. In fact, 90% of false triggering originates from 7 types of common interference sources. In this article, we will teach you to troubleshoot and solve the problem, so that the sensor to restore accurate work!

I. Analysis of sources of interference

1. Heat source interference (air conditioning/heating/sunlight)

(a) Phenomenon: Frequent false triggering when no one is moving.

(b)Principle: The PIR sensor works by detecting changes in temperature, and heat sources such as heating vents and western exposure windows can be misjudged as the human body.

(c) Solution:
(a) Adjust the installation position to avoid the air conditioner direct blowing area.
(b) Select double identification sensor (infrared + microwave composite detection).
(c) Avoid installing next to a window in direct sunlight (can add a light shield)

2. Electromagnetic interference:

(1) Phenomena: The starting and stopping of high-power inductive loads in the power grid generates sharp pulse interference, and voltage fluctuations in the industrial power grid can also affect the sensors. In addition, the intersection of sensor power supply lines and power lines such as motors can bring about radiation and coupling interference.

(2) Solution:

(a) Metal shielding: copper/aluminum shielding wrapped around sensitive circuits can attenuate more than 30dB of radiated interference, especially for current sensors near motor controllers in new energy vehicles.

(b) Flexible shielding materials: graphene coating or liquid metal coating to achieve lightweight electromagnetic shielding, suitable for flexible sensors in wearable devices.

3. Pet/critter activity Interference

(a) Phenomenon: Lights turn on for no apparent reason when pets pass by.

(b) Principle: Conventional PIR cannot distinguish between humans and small animals (especially large dogs).

(c) Solution:
(a) Select pet-proof model (e.g. sensitivity adjustable to ≥20kg biological trigger).
(b) Installation height ≥ 2 meters and tilt downward (to reduce the probability of ground pet triggering)

4. Temperature interference:

(a) Phenomenon: Infrared sensors in high temperature environments, such as summer, may have difficulty accurately distinguishing between people and background environments due to ambient temperatures close to human body temperature, resulting in false alarms.

(b) Solutions:

(a) Wrapping the sensor with an insulating material (e.g. polyimide film) to block external thermal radiation

(b) Installation away from heat sources (e.g., motors, heat sinks) at a distance of ≥15cm.

5. Reflective surfaces (glass/mirror)

(a) Phenomenon: The sensor reacts to activity outside the window or in the next room.

(b) Principle: Infrared rays are reflected by mirrors, expanding the monitoring range.

(c) Solution:
(a) Adjust the sensor angle to avoid reflective objects.
(b) Change to radar sensor (not affected by reflections)

6. Electronic equipment interference (routers/microwave ovens)

(a) Phenomenon: Intermittent sensor failure or chaotic triggering.

(b) Principle: 2.4GHz Wi-Fi signal conflicts with some sensor wireless protocols.

(c) Solution:
(a) Distance the sensor from the router by ≥ 3 meters.
(b) Replace the sensor with Zigbee protocol sensor (stronger anti-interference).

7. Misclassification of stationary objects (curtains/vegetation swaying)

(a) Phenomenon: Curtain fluttering triggers sensing.

(b) Principle: Radar is sensitive to micromotion and may misidentify windblown objects as people.

(c) Solution:
(a)Set the detection distance in APP (e.g. only monitor the area within 1 meter).
(b) Enable static object filtering (supported by high-end models)

二: Summarize:

False triggering of the human body sensor is not a quality problem, but an environmental adaptation problem! According to the steps in this article, 90% of the problem can be solved. If you still have questions, welcome to leave a message to discuss!