Why Won't My SimpliSafe Motion Sensor Work Properly?

Problem Description

Your SimpliSafe motion sensor is not detecting motion reliably or triggering false alarms. Adjust the sensitivity for your environment — the motion sensor uses PIR (passive infrared) detection and can be set to different sensitivity levels. Pets, HVAC airflow, and direct sunlight through windows can cause false triggers. This guide covers sensitivity adjustment and best mounting height and angle.

Why This Happens in Real Homes

A motion sensor that misses real motion usually has sensitivity set wrong, is mounted too high or low, or is out of range of the base. PIR needs subjects to cross its detection pattern, so placement and aim decide coverage.

Start by mounting it at the recommended 4-5 feet, angled to cover the room's walk path — people crossing its field trip it better than walking straight at it — and check it's within base-station range. Raise sensitivity if it's missing events, and confirm the battery is good.

Symptoms

• Doesn't detect people walking by
• False alarms from pets
• Triggers randomly at night
• Not responding to test
• Shows inactive in app

Recognize these? Here's what usually causes it.

Common Causes

• Sensitivity set wrong
• Mounted too high/low
• Pet immunity not working
• Battery depleted
• Heat sources nearby

Tools & Requirements

Step-by-Step Solution

1

Adjust sensitivity for your environment

The SimpliSafe motion sensor has sensitivity settings accessible in the SimpliSafe app. If you are getting false alarms, reduce the sensitivity. If you are missing events, increase it. The sensor detects infrared heat changes, so moving heat sources (HVAC vents, space heaters, sunlight patches that move across the floor) can trigger false alarms. Aim the sensor away from these heat sources.

2

Configure pet immunity correctly

SimpliSafe motion sensors generally ignore pets under 50-60 pounds (Gen 2) or under 30 pounds (original sensors). Enable pet mode in the SimpliSafe app to activate the pet-immune detection pattern. For better pet immunity, mount the sensor 6-10 feet off the ground pointing slightly downward. Pets that jump on furniture or climb to sensor height will still trigger the sensor regardless of pet mode settings.

3

Mount the sensor at the correct height and angle

SimpliSafe recommends mounting the motion sensor at about 7 feet high on a wall, in a corner if possible. At this height, the detection pattern covers the room while minimizing floor-level pet triggers. If mounted too low (4-5 feet), it detects pets and small children much more readily. In pet homes, some users mount the sensor upside down (test button on top) to create a higher detection floor.

4

Eliminate environmental false alarm sources

Common false alarm sources: direct sunlight hitting the sensor lens (the heat changes as clouds pass trigger the PIR), HVAC vents blowing warm or cold air across the sensor field, ceiling fans creating air movement, and reflective objects (mirrors, glass tables) that redirect heat signatures. Move the sensor or block the problematic heat source.

5

Replace the battery and re-test

Low battery causes erratic behavior — intermittent detection, false alarms, or complete failure. Replace the battery (CR123A for most SimpliSafe motion sensors) with a fresh brand-name battery. After replacement, walk through the sensor detection area and verify it triggers correctly. If the sensor continues to malfunction with a new battery, it may need replacement.

Needed for this step

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Quick Solutions

Still having issues? This is usually the deeper cause below.

Need More Help? SimpliSafe Support

Note: The contact information below connects you directly to SimpliSafe's official customer support team, not Trunetto. They can help with warranty claims, device replacements, and advanced technical issues.

How Does SimpliSafe Compare?

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