A study of non-exercise activity thermogenesis using lego sensors

• Main Author: Koh, Veronica Wei Ping.
• Other Authors: Chen I-Ming
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Mechanical engineering::Bio-mechatronics
• Online Access: http://hdl.handle.net/10356/39759
• Institution: Nanyang Technological University

According to the world health organization (WHO), there are one billion adults globally who are overweight and 300 million of them are obese. This increase in obesity has led to increased popularity of activity monitors such as pedometers, which help to estimate energy expenditure and other parameters such as the number of steps taken daily. In this study, the focus is on non-exercise activity thermogenesis (NEAT), which is an important component of an individual’s total daily energy expenditure (TDEE). In particular, three non-exercise activities investigated include sitting, standing and walking at different speeds and the parameters of interest are steps taken, time allocation for different activities and energy expenditure. A Lego NXT controller and a third party acceleration sensor were used to investigate NEAT due to their ease of usage and availability of programming resources. RobotC and MATLAB programming algorithms were developed for data acquisition and analysis of signals. Various studies were conducted in this project with the acceleration sensor either mounted on the thigh or the hip to capture human motion. The different studies were conducted with the aim of estimating parameters optimally with acceptable accuracy, as well as sufficiently long period of activity monitoring. The effect of sampling frequency on steps estimation accuracy was studied to obtain an optimal frequency of about 5Hz, where percentage error for steps estimation was minimal. Filtering algorithm of the acceleration signals was also developed using MATLAB to reduce noise and increase steps estimation accuracy. In order to overcome data space limitation of the NXT controller, adaptive sampling for sensor readings was also developed to increase sampling frequency during more dynamic motion like walking and reduce it during relatively static motion like sitting and standing.