Abstract: A portable grating spectrometer based on the Internet of Things is designed to visually demonstrate the working principle of the grating spectrometer in the undergraduate practical teaching process. The STM32 is used as the main controller. The off-chip circuits include the array photodiode light intensity signal acquisition module, the analog-to-digital conversion module, the stepper motor drive module and the Wi-Fi communication module. The optical system of the spectrometer is simulated, analyzed and optimized by using the optical design software Zemax. The software part is developed using JAVA and C/ C + + languages. Relying on the Keil development environment, the underlying program of the hardware system is written, and a spectral analysis platform based on wechat mini-program was developed as a supporting tool. To verify the system performance, a standard mercury lamp light source is selected for spectral testing, and the obtained spectral data is compared with the reference spectra of commercial spectrometers. The experimental results show that the measurement of this system are reliable and its performance meets the requirements of teaching demonstrations. This research provides a feasible solution for the development of a low-cost and highly demonstrable grating spectrometer for teaching purposes, which has certain value for promotion and application. 

Key words: spectrometer, grating, Zemax software, WeChat mini programs, internet of things