Alarm PIR Sensors

Alarm PIR Sensor

Alarm PIR Sensor

PIR Sensor in the Obsessive Van with internal sirens and LED light bar

Alarm PIR sensors (passive infrared) detect infrared light (heat energy) which radiates from objects in its field of vision such as a human body. This makes them great for protecting Ute canopies or the back or vans where a solid cargo barrier prevents Ultrasonic Sensors covering the space.

PIR Hilux

PIR Sensor installed in a Ute canopy.

Installation methods

There are two ways to connect a PIR sensor up to an alarm. The first method is to wire the sensor up to the alarms AUX input. Most decent alarms give the user the option to disable the AUX input on the alarm whilst still having the door and bonnet triggers active so that the vehicle can be locked and armed with the PIR sensor turned off if desired.

Upgrade alarm method

Alarm PIR sensor mounted with custom bracket

PIR sensor mounted with a custom bracket for a tidy and solid installation.

One common issue when installing a PIR sensor in a Ute is the alarm re-arming. It’s mainly an issue with upgrade alarms.

The Ute gets unlocked (alarm is disarmed) and the vehicle will re-lock and in turn re-arm the alarm if a door is not opened after a set time (normally about 30 seconds).

This can then catch the owner out if they only wish to access tools or such in the canopy and not access the main vehicle. As soon as they trigger the PIR sensor then the alarm sounds! Whilst the user could simply open and shut one of the doors to stop this from happening most people don’t find this very convenient.

Wiring the PIR sensor via a relay to one of the doors will trick the vehicle into thinking that a door has been opened as soon as the PIR sensor detects movement. This will then prevent the vehicle from re-locking and re-arming, and getting triggered by mistake.

The downside to the method is that you need to be aware and remember how it works. Also having a dog in the back would cause the door open warning light to flash each time the dog moved which would also turn the internal lamp on and off! There is a better solution:

Remote Double Tap Module

The Remote Double Tap Module works with the existing remote and simply prevents the vehicle from re-locking if the remote unlock button is pressed twice. It can also be used to unlock the canopy where electronic locks are fitted. More details here…

Wireless PIR

Autowatch makes a wireless PIR sensor. Details can be found here:


About Julian

Owner and Installer at Obsessive Vehicle Security Limited. More details here... Please keep Comments relevant to the post and use the Contact form for enquiry's
This entry was posted in Car Alarms, Car Security, Sensors. Bookmark the permalink.

3 Responses to Alarm PIR Sensors

  1. Avatar Peter Boyce says:

    I have an issue with the PRI in the back of my ute canopy setting the alarm off randomly?
    The canopy is secure, and no windows are open.
    Is there anything I should look for before I disconnect it?

  2. Julian Julian says:

    Hi Peter,

    I’d make sure that the sensor is clean and cobweb free. I assume you have an alarm fault code indicating that it is the PIR Sensor? Have you disabled the sensor when arming?

  3. Avatar Julia says:

    Hi Peter,
    A couple of other things to check before throwing the towel in with your PIR, are, where the vehicle is parked, can the PIR receive direct illumination by sunlight or strong reflection of sunlight? This can is some situations saturate the silicon inside the PIR can cause false positive readings ( aka activations)
    The second is, especially in summer, is the ventilation in your canopy working effectively to limit the heat build up inside the canopy? If not again, there is a point where the PIR can become saturated. that much heat isn’t good for you, or your tools either.

    Caviat: unlike Julian, my experience is with security systems for buildings. accuracy for a vehicle market not guaranteed.

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