Keeratirawee Kanchalar, Furter Jasmine S, Hauser Peter C
University of Basel, Department of Chemistry, Klingelbergstrasse 80, 4056 Basel, Switzerland.
Department of Applied Science and Business Management, King Mongkut's Institute of Technology Ladkrabang, Prince of Chumphon Campus, Chumphon 86160, Thailand.
HardwareX. 2022 Feb 16;11:e00280. doi: 10.1016/j.ohx.2022.e00280. eCollection 2022 Apr.
The circuitry comprises a sine wave generator based on direct digital synthesis, a laser diode driver module, a band-pass frequency filter, a synchronous detector with phase adjustment circuitry and a low pass filter to form an analog lock-in amplifier, and an analog-to-digital converter. A 32-bit ARM microcontroller programmed with the open source Mecrisp dialect of the Forth interpreter language is used to set the frequency, and read the data from the analog-to-digital converter. The circuitry is tethered via a serial interface to a personal computer. A graphical user interface written in Phython allows easy interaction with the microcontroller by sending the appropriate Forth commands. The data acquired is visualized and stored on the personal computer for further processing. The circuitry is easy to build as it is based on through-hole devices, except for two necessary surface mount items, which, however, still can be soldered with a fine tipped soldering iron. The performance of the circuitry was demonstrated by the photoacoustic detection of NO using a laser diode with a wavelength of 450 nm.
该电路包括一个基于直接数字合成的正弦波发生器、一个激光二极管驱动模块、一个带通频率滤波器、一个带有相位调整电路的同步检测器和一个低通滤波器以形成一个模拟锁相放大器，以及一个模数转换器。一个用开源的Forth解释器语言的Mecrisp方言编程的32位ARM微控制器用于设置频率，并从模数转换器读取数据。该电路通过串行接口连接到个人计算机。用Python编写的图形用户界面允许通过发送适当的Forth命令与微控制器轻松交互。采集到的数据在个人计算机上进行可视化和存储，以供进一步处理。该电路易于构建，因为它基于通孔器件，除了两个必要的表面贴装元件，不过这两个元件仍然可以用细尖烙铁进行焊接。该电路的性能通过使用波长为450 nm的激光二极管对NO进行光声检测得到了证明。
