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December 1st, 2015

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All of these types of driveway alarms use what is called passive infrared sensor technology. They work by detecting moving heat. One common cause for these units to be ‘missing’ vehicles in the winter is that the vehicle simply has not warmed up yet. It’s normal for a vehicle which was just started up and is leaving the property to not trip these sensors in the winter as the engine is not warm enough yet to be detected.