1. Because the threshold for light and darkness can vary depending on the location and the sensor, commercialization may be difficult with the current approach.

2. When shadows overlap, measurement errors can easily occur.

The system could be further improved by incorporating other types of sensors (e.g., weight sensors).

Through this project, we were able to turn our ideas into reality while also facing many unexpected challenges. It became a valuable opportunity to think about how to respond to different problems as they arise.

In particular, while designing the circuit with Arduino and experimenting with ultrasonic and light sensors to count passengers, we realized that it was difficult to obtain precise values because distance and brightness produce continuous readings. This experience taught us the limitations of our chosen approach.

We concluded that using weight sensors or card reader sensors could provide a more accurate and efficient way to track the number of passengers inside the bus in the future.