the flowchart shown that is explains about light sensor and buzzer.When press the button to start the light sensor system on peripheral to meter when a passenger using the service. When a passenger bring your baggage to put on the car ,then light sensor will detecting a baggage .If it's have a baggage , laser light is sent to the light sensor will cut through the baggage of the passenger. Make the light can not be shining on the light sensor. Thus,it's show the results as the pressure lower than 2V system and know that there is a baggage on the car, but will not display until the passenger will pay each carrier to hold the meter. When a passenger press the botton to check a baggage