1) The document proposes an IOT-based step lock system for buses using sensors to prevent footboard accidents.
2) An ultrasonic sensor is mounted on the bus footboard and an IR sensor is attached to the front wheel to detect passengers and bus motion.
3) When passengers are detected on the footboard while the bus is moving, a buzzer will sound and a message will display on an LCD to warn passengers not to stand on the footboard. The system aims to increase passenger safety.