Development of a Locally-made Digital Tachometer

Abstract

The exact measurement of rotational speed is an important parameter for monitoring and controlling mechanical systems such as motors, turbines, and automotive engines. This paper presents the design and evaluation of a low-cost digital tachometer that is locally produced using a Hall Effect sensor and an Arduino microcontroller. The tachometer was developed to accurately measure rotational speed for educational and industrial purposes while being less expensive than commercial tachometers. The fabricated device was evaluated using an electric motor, a mini hand fan, and an automobile radiator fan. The fabricated tachometer's measurements were then compared to Hall Effect-based commercial tachometers to evaluate their accuracy and reliability. Results showed that all tests had a very small difference between the fabricated tachometer and the commercial tachometers, showing that the measurements were accurate. The locally manufactured device had a shift of ±2.60 RPM, ±3.07 RPM, and ±2.57 RPM for the electric motor, mini hand fan, and automobile radiator fan, respectively. The overall efficiency is 97%. Therefore, the Hall Effect sensor and Arduino system could be used to monitor speed. One key idea of this research was to provide a low-cost option of a tachometer rather than one from a foreign country to enhance learning and use in industry. The instrument will provide an in-class mechanism for teaching engineering students instead of purchasing higher and probably unneeded foreign tachometers. Overall, the instrument will add a hands-on learning experience to engineering education while providing a low-cost option for an academic institution or small business.