2025 ASEE Annual Conference & Exposition

Introducing Angle Sensors into Robot Block Teaching Kits Using Non-Contact Magnetic Rotary Encoder

Presented at Multidisciplinary Engineering Division (MULTI) Technical Session 2

Title:
Introducing Angle Sensors into Robot Block Teaching Kits Using Non-Contact Magnetic Rotary Encoder

Abstract:
Rotary encoders are integral components in mechatronics and are widely used to measure shaft angles across various systems. However, integrating them into educational robot block kits poses several challenges. Conventional rotary encoders are costly ($100–$140), bulky due to precision mechanical components and optical systems, and require high torque to rotate their shafts. These characteristics make them unsuitable for educational environments, where simplicity, affordability, and low mechanical load are essential. Furthermore, incremental encoders produce pulse signals that are difficult for beginners to interpret, limiting their educational utility.

This study presents a practical and cost-effective alternative by incorporating a non-contact magnetic rotary encoder into robot block kits. The AS5048B encoder from ams-OSRAM AG was selected for its compact surface-mount design, high angular resolution (14-bit; 0.022° per step), and affordability (approximately $10). Unlike traditional encoders, the AS5048B measures angular position through magnetic field detection without physical contact, and outputs angle data via either I2C digital communication or a PWM signal. Since typical educational kits lack a general I2C interface, the PWM output (1 kHz, 4119 steps) was converted into an analog voltage using a custom-designed RC low-pass filter, ensuring compatibility with conventional analog input systems. The filter was optimized to balance measurement accuracy and response time.

A prototype sensor block was integrated into a robot block kit and tested in an inverted pendulum experiment. The system exhibited stable analog output, with a maximum angular error of ±4.5°, occurring at a 50% PWM duty cycle. These results demonstrate that the proposed encoder solution maintains high precision and reliability while substantially reducing both cost and system complexity. This approach supports real-time feedback control exercises using affordable, beginner-friendly components, thereby enhancing accessibility to hands-on robotics education.

Authors

Dr. Sumito Nagasawa http://orcid.org/0000-0003-4684-2898 Shibaura Institute of Technology [biography]

Prof. Dr. Sumito Nagasawa received Ph.D. in Engineering from the University of Tokyo in 2001. He is a Professor in Department of Engineering Science and Mechanics at SIT. His research interests include miniaturized robots using Micro-Electro-Mechanical Systems technologies and robot education for STEAM.
Prof. Hatsuko Yoshikubo Ph.D. SHIBAURA INSTITUTE OF TECHNOLOGY [biography]

Dr. Hatsuko Yoshikubo obtained Ph. D. in English Literature from Chiba University in Japan in 2002. She is currently a Professor of Humanities and a senior departmental administrator, currently attached to the Innovative Global Program in the College of Engineering at Shibaura Institute of Technology, a highly-ranked engineering university in Tokyo. Innovative Global Program (IGP) is an engineering degree program incorporating humanities components, with a student body consisting mainly of international students (https://igp.shibaura-it.ac.jp).

As part of her current role as Deputy Director of the IGP, she is the Principal Investigator for the following research grants:
- Japan Society for the Promotion of Science Research: Grant 24K06133 (2024-2027)
- Shibaura Institute of Technology Grant for Educational Reform and Research Activity (AY2024).

Her research interests include:
(1) Impacts and potential benefits of including humanities components in science and engineering degree programs
(2) Innovative methods of assessment in science and engineering education, especially in the context of remote learning, hybrid courses, and collaborative international programs
(3) Solving systematic issues that impact the effectiveness of science and engineering education programs, in both in-person and remote learning contexts.

In recent years she has been a presenter at the following international conferences:
World Educational Research Association (WERA):
WERA Conference 2019, 2022, 2023, 2024
Asia-Pacific Association for International Education (APAIE):
APAIE Conference 2022, 2023,
American Society for Engineering Education (ASEE): Annual Conference 2022, 2023, 2024
International Institute of Applied Informatics (IIAI): International Conference on Data Science and Institutional Research (DSIR) 2023

Awards:
SIT's Presidential Award 2023
ASEE 2023: Multidisciplinary Engineering Division’s 'Best Diversity Paper' Award
DSIR 2021: 'Outstanding Paper' Award

Note

The full paper will be available to logged in and registered conference attendees once the conference starts on June 22, 2025, and to all visitors after the conference ends on June 25, 2025

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