无弦激光音乐琴是一种理想的集观赏与娱乐为一体的琴，可作为课程辅助教学仪器或者儿童玩具，具有十分重要的商业价值。本文设计了一款集激光、单片机、机械、电路于一体的无弦激光音乐琴系统，主要包括多路激光模块、激光传感器模块、控制器模块以及音乐响应模块，为了实现对激光信号灵敏探测，主要针对整体电路和程序进行了设计。采用5 mW、650 nm半导体激光器作为发射源，采用光敏电阻作为接收器接收激光信号，经过STC89C52单片机的控制处理及LM386音乐响应模块的功率放大，实现音频输出。完成了无弦激光音乐琴系统的制作，整体尺寸为长10 cm × 宽5 cm × 高11 cm。对该系统发声频率进行了实验研究，可实现3个音阶，7个音调的演奏，音色清晰，实测音调频率与理论计算音调频率偏差不大于7.098 Hz。
The string-less laser music piano is an ideal instrument for viewing and entertainment, which can be used as an auxiliary teaching instrument or children’s toy, and has very important commercial value. A string-less laser music piano system, integrating laser, single chip microcomputer, machinery and circuit, is designed in this paper, which mainly includes multi-channel laser module, laser sensor module, controller module and music response module. In order to realize the sensitive detection of laser signal, the whole circuit and program are designed. The semiconductor laser with power of 5 mW and wavelength of 650 nm is used as the source, and the photosensitive resistor is used as the receiver to receive the laser signal. After the control and processing of STC89C52 single-chip microcomputer and the power amplification of LM386 music response module, audio output is realized. A string-less laser music instrument system with a size of 10 cm length × 5 cm width × 11 cm height was made, and the sound frequency was studied experimentally. It can play 7 scales and 3 tones with clear timbre. The deviation between the measured tone frequency and the calculated tone frequency is no more than 7.098 Hz.
