Bidirectional detection with ultrasonic sensors

   I will made a box with 2 doors and system need to detect movement so I tested a simple system with Arduino board and 2 ultrasonic sensors (HC-SR04).

   I used info from an old project (made a 7 yesrs ago)

   New test schematic is

   My program is bidirectional_detection_ultrasonic.ino and if any sensor detect an object bellow 25cm led is turned on for 3 seconds.

   I made 2 video with this system: