The first sensor used is Light Dependent Resistor (LDR) Sensor. LDR sensor is integrated with crossbow’s
MDA100CA sensor board28. The LDR sensor works on shadow detection method. In shadow detection method,
whenever there is presence of light or luminous source such as Sun, it calculates the luminous intensity.29. The absence
of luminous intensity creates a shadow. If an LDR sensor is deployed beneath a vehicle, the presence of a
vehicle creates a shadow over the LDR sensor. Indicating unavailability of a parking slot. Similarly, the absence of
vehicle will not create any shadow. Indicating availability of a parking slot. In this way, LDR sensor is used to detect
the vehicle in smart parking system.