"多功能视力保护器设计：解决青少年近视问题的智能方案"

In China, juvenile myopia has become an increasingly serious social issue. Myopia, as a modern common disease, almost has no way to cure it. Currently, laser surgery actually harms the natural integrity of the human body and damages physical and mental health. Therefore, for centuries, people have been using the "glass concave-convex" method to maintain people's search for the outside world. Research shows that 99% of myopia is caused by children sitting improperly while reading or writing, resulting in the eyes being too close to the book. This design is mainly composed of three circuits: distance detection circuit, light intensity detection circuit, and timing circuit. The distance detection circuit uses the principle of ultrasonic reflection, where the transmitter emits oscillating pulses, which are then received by the receiver after reflection. The received signal is amplified by an amplification circuit to drive the indicator light to flash, achieving distance detection and alarm functions. The light intensity detection circuit uses the light-sensitive resistance to detect changes in external light intensity, reminding the user to adjust the light intensity. The timing function is mainly implemented using the timing function of the CD4060 chip. I used the STC89C52 single-chip microcontroller to control the entire system, with automatic light adjustment functionality to correctly adjust the brightness. It controls the sitting posture correction by sensing the position of the human body using sensors to determine whether to turn on or off, or to issue corresponding warning signals. Keywords: STC89C52; ultrasonic; light-sensitive resistance; CD4060 chip.