DC Motor Monitoring and Diagnostic System using Optical Encoder and ESP32 with Embedded Web Server

Abstract

Accurate measurement of angular velocity in DC motors is essential for industrial and educational applications; however, commercial tachometers present high costs that limit their accessibility. This work presents the design and implementation of a low-cost DC motor monitoring and diagnostic system based on the HC020K optical encoder and ESP32 microcontroller, with an embedded web server for remote data visualization. The system measures angular velocity through interrupt-based pulse counting, calculating revolutions per minute (RPM) from the frequency of the 20-slot encoder signal. Experimental tests conducted at 3V, 5V, and 6V showed relative errors between 3.8% and 5.8% compared to the manufacturer's specifi cations for the DC TT motor with 1:90 gear ratio, validating the system's accuracy (>94%). The implemented web server enables real-time remote control and monitoring via WiFi, presenting perfect agreement (0% error) with direct acquisition under 3V and 5V conditions, and 3.6% at 6V. The results demonstrate that the proposed system constitutes a viable, accessible, and accurate alternative for velocity measurement applications in industrial, educational, and research environments, with a cost reduction greater than 85% compared to traditional commercial solutions.