Physical activity assessment is useful for determining both physical and mental health. The measurement of activity has been performed by several techniques such as direct observations, subjective reports, metabolic measurements and portable physical activity monitors.
Each type of technique has certain strengths and weaknesses. Recently, studies on portable physical activity monitors have been increasing and presented good assessment results.
Upon consideration of the characteristics of the portable monitors such as being unconstrained and long-term monitoring, an indoor portable monitor was designed and developed.
It measures three dimensional acceleration and transfers data by Zigbee protocol wirelessly. This system could help to assess daily activity without subject's consciousness .