Motion Detection on Smart Battery Cameras with a PIR Sensor

Our Smart Battery Cameras use a PIR sensor (Passive Infrared) for motion detection. This sensor works differently from motion detection systems that continuously analyse camera footage.

If your camera does not detect motion, or only detects it occasionally, this does not necessarily mean that the camera is defective. The performance of a PIR sensor is influenced by several factors, including mounting height, viewing angle, distance, ambient temperature and possible obstacles.

Below, we explain how PIR motion detection works, which conditions can affect its performance, and how you can check whether your camera is functioning correctly.

1. How does a PIR sensor work?

A PIR sensor does not detect motion by analysing camera footage. Instead, it responds to changes in infrared heat radiation within its detection area.

For example, when a person walks through the detection area, the sensor can detect the difference between the infrared radiation emitted by that person and the surrounding environment. When this change is sufficiently large, the PIR sensor is triggered, allowing the camera to start recording or send a motion notification.

A PIR sensor has multiple detection zones. The direction in which someone moves through these zones plays an important role in how reliably motion is detected.

Movement from left to right or vice versa

When a person walks across the detection area, they pass through multiple detection zones. This generally makes it easier for the PIR sensor to recognise changes in infrared radiation.

Movement directly towards or away from the camera

When a person walks directly towards or away from the camera, they may remain within the same detection zone for longer. As a result, changes in infrared radiation may be less noticeable, causing motion to be detected later or not at all.

Important: The PIR sensor detects changes in infrared radiation and does not recognise people itself. If your camera also supports person detection, this feature is only activated after the PIR sensor has triggered the camera.

2. Which factors affect motion detection?

Mounting height and viewing angle

The mounting height and the angle at which the camera is positioned determine which area the PIR sensor can monitor.

If a camera is mounted too high or angled too far downwards, the effective detection area may become smaller or incorrectly positioned.

As a result, a person may be clearly visible in the camera's field of view while remaining outside the effective detection area of the PIR sensor.

A mounting height of approximately 2 to 2.5 metres is a suitable starting point for many battery-powered cameras. However, the ideal mounting height may vary depending on the camera model and installation conditions.

Distance from the camera

A PIR sensor has a limited detection range. As a person moves further away from the camera, it becomes more difficult to reliably detect changes in infrared radiation.

For cameras with adjustable PIR sensitivity, the following approximate detection distances are commonly used in practice:

These distances depend on the camera model and apply under favourable conditions. They are not guaranteed detection ranges.

Even at high sensitivity, the actual detection distance may be shorter due to the mounting angle, temperature or surrounding environment.

Obstacles within the detection area

A PIR sensor needs a sufficiently unobstructed view of the area where motion should be detected.

Objects such as walls, fences, posts, furniture, bushes and other obstacles can block infrared radiation.

As a result, a person may be partially visible in the camera footage but may not be sufficiently detected by the PIR sensor.

Glass is another important limitation. A PIR sensor generally cannot reliably detect infrared radiation from a person through an ordinary glass window.

Ambient temperature and weather conditions

A PIR sensor works by detecting temperature differences.

When the ambient temperature is close to a person's surface temperature, the difference in infrared radiation may become smaller. This can make the sensor less responsive.

Direct sunlight, surfaces that become very warm, moving warm air and changing weather conditions can also affect detection performance or cause unwanted activations.

Movement speed and direction

Not only distance, but also the way a person moves, is important.

A person walking across the detection area is generally easier to detect than someone slowly approaching the camera directly.

Very slow movements or people who remain almost stationary may also be more difficult to detect.

PIR sensitivity

On cameras with adjustable PIR sensitivity, you can change the sensitivity level in the app.

Increasing the sensitivity may help detect movement at greater distances or smaller changes in infrared radiation.

However, this does not guarantee that every movement will be recorded. Higher sensitivity may also result in more unwanted activations and increased battery consumption.

Power saving and reactivation

Smart Battery Cameras are designed to operate as efficiently as possible to conserve battery power.

For this reason, these cameras normally remain in a power-saving mode. When the PIR sensor detects motion, the camera is activated.

Depending on the camera model and its settings, there may be a short period after a detection event during which the camera cannot immediately be triggered again. This is also known as a cooldown period or reactivation interval.

As a result, consecutive movements may not always be recorded as separate events.

Additionally, activating the camera after a PIR trigger may take a short amount of time. This means that the beginning of a movement may not always be visible in the recording.

3. Why is someone visible in the live view but not detected?

This is a common question.

The camera's field of view and the PIR sensor's detection area are not necessarily identical.

The camera may have a relatively wide viewing angle, while the PIR sensor monitors a smaller or differently positioned area.

As a result, a person may be clearly visible in the live view while remaining outside the effective detection area of the PIR sensor.

Just because someone is visible in the camera footage does not automatically mean that the PIR sensor can detect them.

Furthermore, the camera can only start recording once the PIR sensor has detected a sufficient change in infrared radiation.

4. How to test motion detection yourself

The following steps will help you check whether the PIR sensor is functioning correctly and identify which conditions may be affecting motion detection.

Step 1 – Check the settings

Open the Smart app and check your camera's settings.

• Make sure motion detection is enabled.
• If available, temporarily set the PIR sensitivity to High.
• Check that no detection schedule is active that could temporarily disable motion detection.
• Check whether sleep modes or power-saving settings are limiting motion detection.
• Check whether a firmware update is available for your camera.
• Make sure the battery is sufficiently charged.

The available settings may vary depending on the camera model.

Step 2 – Test at a short distance

Stand approximately 2 to 3 metres away from the camera.

Slowly walk from left to right across the detection area.

Wait long enough between each test to ensure that any reactivation interval does not affect the results.

Repeat this test at least three times.

Result: If the camera consistently detects you during this test, this is a strong indication that the PIR sensor is functioning.

Step 3 – Test at different distances

Repeat the test at approximately 4, 6 and 8 metres, provided these distances are within the specified detection range of your camera model.

At each distance, walk across the detection area.

Check at which distances the camera still responds reliably.

Result: If motion detection works correctly at short distances but not at greater distances, this may be caused by the sensitivity setting, viewing angle, mounting height or environmental conditions.

Step 4 – Test different movement directions

Perform two separate tests:

Test A: Walk from left to right across the detection area.

Test B: From the same distance, walk directly towards the camera.

Compare the results.

Result: If movement from left to right is detected but movement directly towards the camera is not detected, or is detected less reliably, this may be explained by the way the PIR detection zones operate.

Step 5 – Check the mounting angle and obstacles

Make sure the PIR sensor has an unobstructed view of the area you want to monitor.

Check the following:

• Is the camera installed at the recommended mounting height?
• Is the camera possibly angled too far downwards?
• Are there any obstacles between the camera and the detection area?
• Is the area where you want motion to be detected located near the edge of the camera's field of view?
• Is the camera installed behind glass or another material that could block infrared radiation?

If possible, slightly adjust the camera angle and repeat the test.

Result: If motion detection improves after adjusting the viewing angle, the original camera position was probably not optimal for the PIR sensor.

Step 6 – Temporarily test the camera in another location

If the previous steps do not provide a clear result, we recommend temporarily testing the camera in a different location.

Preferably choose an open area without obstacles, with a suitable mounting height and a clear, unobstructed view.

Repeat the test at approximately 2 to 3 metres by walking from left to right across the detection area.

Result: If the camera consistently detects motion in this location, this suggests that the original mounting position or surrounding environment is affecting its performance.

If the camera still fails to detect motion, or only responds occasionally under these favourable conditions, further technical investigation may be necessary.

5. Motion detection and push notifications are not the same

It is important to distinguish between detecting motion and receiving a notification on your smartphone.

When the PIR sensor detects motion, the camera can start recording and send a notification through the app.

If the camera records motion events but you do not receive push notifications, this does not necessarily mean that the PIR sensor is malfunctioning.

In this situation, we recommend checking the following:

• Are push notifications enabled for the camera in the app?
• Does the app have permission to display notifications on your smartphone?
• Is the camera connected to a stable Wi-Fi network?
• Does the camera have a working internet connection?
• Are there any power-saving settings on your smartphone that may restrict notifications?

We therefore recommend first checking whether the camera has actually registered a motion event before concluding that the PIR sensor is not functioning correctly.

6. What if motion detection still does not work properly?

If your camera still does not reliably detect motion after completing the tests above, we will be happy to assist you further. To investigate the issue, we need some additional information.

This will help us assess the installation and operation of your camera more accurately.

Please provide the following information:

1. The exact product/article number of your camera.
2. The device ID of your camera, so we can check the available technical logs.
3. The mounting height of the camera, measured from the ground.
4. A screenshot of the camera's live view, showing the entire monitored area.
5. The configured PIR sensitivity (Low, Medium or High).
6. The approximate distance at which motion is not detected or is detected unreliably.
7. The results of the tests you performed, including any differences between movement from left to right and movement directly towards the camera.

Please also let us know whether the camera does not detect any motion at all, occasionally misses movement, or records motion events but does not send notifications.

With this information, we can better determine whether the issue may be related to the mounting position, camera settings, environmental conditions or the operation of the camera itself.

Final remarks

A PIR sensor provides an energy-efficient way to detect motion, making it particularly suitable for battery-powered cameras. However, its performance depends on the conditions in which the camera is used.

Mounting height, viewing angle, detection distance, movement direction and the presence of obstacles all affect detection reliability.

Even when a PIR sensor is functioning correctly, certain movements may not be detected. Therefore, a PIR sensor cannot guarantee that every person or movement will be detected under all circumstances.

By following the tests described above, you can often identify which factors are affecting motion detection and whether adjusting the installation may improve performance.

If you continue to experience problems after completing these tests, we will be happy to assist you further using the additional information requested above.