This document proposes using a PIC microcontroller to control the angular movement of a laser beam in a surface plasmon resonance (SPR) instrument. SPR analysis is an important optical biosensing technique used in medical, biological and other research. The SPR works by focusing a laser beam from a stepper motor-mounted laser onto a gold-coated prism surface at an angle greater than the critical angle, generating SPR outward. Changes in the refractive index from applied samples can be detected. The document describes a laboratory prototype using a PIC microcontroller to control the stepper motor movement of the laser, allowing for faster and more accurate SPR analysis and demonstrating the importance of microcontrollers in instrument design and control.