Development of Sensing Device to Detect Persons Hiding in a Car

This paper describes a novel method for detecting the presence of a person hiding in a car. One of the important strategies of homeland security is border control. In particular, strict and effective monitoring to control illegal immigration is a key strategy for maintaining public safety and a healthy local economy, and is essential for preventing the entry of terrorists. Here, we focused on developing a method to detect a person trying to illegally cross the border by hiding in a car. The proposed method is based on pneumatics. A silicon tube (inner diameter 4 mm) with one end plugged by a highly sensitive pressure sensor and the other end capped is sandwiched between two rigid boards and placed on the ground at the entrance gate of the border. When one wheel of the car is on the board and the engine is stopped, the pressure sensor can detect human vital signs such as the heartbeat, which cannot be concealed. Due to the high sensitivity of the pressure sensor, consideration was given to the effect of external disturbances such as ground vibration and wind force acting on the car. Here, we propose a heartbeat detection filter robust against disturbances but sensitive to the heartbeat signal and an index to discriminate between the presence and non-presence of a person, and we present the experimental results obtained using the proposed method under various disturbance conditions.