Design me a Product -- 2

Design the controlling system/circuit for a locker controlled by Android Detail requirement about the locker: - number of independent lockable compartment: 30. - connect to an Android tablet via serial. - receive command from the Android device to open specific compartment. - communicate to Android tablet when a compartment is closed - be able to detect whether there’s object in each compartment. Scope: This project is only about the circuit/ schematic design and programing using Arduino. I will create separate projects for PCB design and the physical 3d modeling for the locker. The output result should include the complete schematics and the Arduino sketch. Skill/Experience preferred: Experience with Arduino as well as 3d modeling/printing.