Passive Infra-Red (PIR) sensors inside the motorhome will detect any movement from anyone who has gain access to the motorhome and set off the alarm, protecting your belongings. Some alarms have the functionality to turn off this feature as a ‘Night’ or ‘Pet’ mode so you can still use the alarm at night whilst you’re asleep and during the day if you leave your pets inside unattended. Some devices may have ultrasonic volumetric sensors that can also detect movement within the vehicle. This kind of motion sensor if often more expensive to manufacture, so you may pay more for an alarm with ultrasonic volumetric sensors than you would for one with PIR sensors, but both methods are effective in preventing theft from motorhomes.