Motion Detection Sensors

What is a Motion Detector security sensor?

A Motion Detector, or Motion Sensor, is a security sensor that detects movement in a designated coverage area. Typically, these devices consist of a lens and passive-infrared sensor (PIR). The device measures infrared light radiating from objects in the lens’ field of view.

Depending on programming conditions and arming status of the panel, triggering a motion sensor can cause an alarm state.

Common Wireless Motion Detector Sensors

Every wireless or hybrid compatible security system works with one or more wireless communication protocols including 319.5MHz, 345Mhz, 433MHz, and PowerG. Part numbers for a variety of the most common sensors can be found below:

2GIG 345MHz Sensors
2GIG PIR1-345 PIR Motion Detector

DSC 433MHz Sensors
DSC WS4904P Motion Sensor

DSC PowerG Sensors
DSC PG9914 PowerG Digital Pet-Immune PIR Motion Detector

Qolsys 319.5MHz Sensors
Qolsys QS1231-840 IQ Motion Detector

Testing a Motion Sensor for Functionality

It is best to test the motion sensor before mounting and after. Before to ensure that the sensor works correctly and communicates with the panel and after to ensure the sensor is being triggered as intended when an object crosses the lens’ field of view and motion is detected. Testing the sensor is as simple as:

  1. Programming the device into the panel.
  2. Leave the panel disarmed and allow the sensor to rest for 3 minutes before testing. Do not cause motion across the lens during this time.
  3. After 3 minutes, walk through the sensors field of vision, or wave your hand across the lens.

When programmed this should cause an activation status at the alarm panel.

After testing the sensor you will want to mount it in its intended location.

Mounting a Motion Sensor

While you should always follow manufacturer guidelines when it comes to mounting specifications, most motions sensors are mounted in a similar fashion. Installation manuals for common sensors can be found below.

  1. Choose the Location: Motion sensors typically should be mounted in the corner of the room, at about 7 to 8 feet off the ground.
    • They should not be mounted near any HVAC vents, sources of heat or humidity, nor should they be facing any windows that get a lot of sunlight. Otherwise you may encounter false triggers.
    • If pets are present, ensure you are using a pet-immune PIR motion and that the animal is under the immunity rating.
  2. Prepare the Surface: Motion sensors come with double-sided foam tape and or mounting screws. If using included foam tape, make sure the area where you will place the sensor and its magnet is clean and dry. This helps ensure the adhesive sticks properly.
  3. Mount the sensor: follow correct orientation and when using screws, follow printed instructions to determine where on the mounting plate the screws go.
  4. Test the sensor: After installation, test the sensor by passing by the sensors field of view. Check your control panel or mobile app to ensure that it registers the activity actions.

Installation Manuals

2GIG PIR1-345 PIR Motion Detector
2GIG-PIR1-345 Installation Manual
DSC WS4904P Motion Sensor
DSC WS4904P Installation Manual
DSC PG9914 PowerG Digital Pet-Immune PIR Motion Detector
DSC PG9914 Installation Manual
Qolsys QS1231-840 IQ Motion Detector
Qolsys QS1231-840 Installation Manual

Common Reasons for False Triggers

  1. Is it mounted per manufacturer instructions?
    • Each Motion Detector will be designed and tested with a specific mounting height. The manual will indicate how high to mount the detector on the wall. Mounting outside of that parameter may cause unexpected behavior.
    • Make sure the detector is away from air vents, fans, and drafts.
    • Do not point the motion detector at windows where sunlight might shine in on the lens.
    • Make sure it is properly angled per instructions if necessary.
  2. Is the sensitivity high?
    • Often detectors will have a sensitivity setting which allows you to fine tune its operation a bit. Try lowering the sensitivity.
  3. Is the Zone Type correct?
    • Motion detectors should use the Interior Follower zone type. This is the zone type that only activates during Away arming.
    • If you have a 2GIG GC3 with firmware 2.2.0 or later, motion detectors must use Interior with Delay zone type instead, due to an unfixed 2GIG bug.
  4. Do you have pets?
    • Cats are a significant false alarm hazard for motion detectors. This is due to their tendency to climb up to locations where the motion detector’s pet immunity has a harder time filtering them.
    • Is the sensor pet immune? Some models of motion detector are not designed for use with pets at all.
    • Try to keep furniture that pets climb on out of range.
  5. Is it a temperature controlled environment?
    • If the sensor is installed in an outdoor/unregulated environment like a garage, barn, shed, etc., it should be an outdoor rated model. A standard indoor sensor will have a variety of potential false alarm/failure causes.