Measuring Microns with Lasers

The Measuring Microns with Lasers project operates on the principle of optical triangulation and high-speed linear detection to measure microscopic displacements. At the heart of the system is a 5 mW-class red laser diode that projects a fine beam onto a target surface. Reflected light from the target passes through a custom stainless steel slot aperture—integrated directly into a PCB stencil—which controls the incoming light profile before it strikes an iC-Haus LFH1024 1,024-pixel linear image sensor. Because the position of the reflected light spot shifts on the pixel array relative to the target's micro-displacement, the linear sensor captures this spatial shift at high speeds. The pixel data is rapidly digitized by an ADC1173 8-bit parallel analog-to-digital converter. Managing this rapid data acquisition stream is a powerful Teensy 4 microcontroller running C++ firmware compiled via the Arduino IDE with Teensyduino. The microcontroller processes the high-rate parallel pixel array data, calculates the centroid or displacement metrics, and streams the results over a serial or USB connection to a host computer. On the host side, a Python application utilizing PySide6 provides a responsive graphical live viewer interface, while an NPZ recorder handles data logging for subsequent analysis. By combining high-speed digital sampling with precise optical apertures, the system achieves sub-micron measurement resolution without relying on bulky or expensive precision camera lenses.