ActimedARM - Design of a wearable system to monitor daily actimetry

Abstract

We developed a low power kinematic sensor, ActimedARM, incorporating three-axis accelerometer and magnetometer, a microcontroller ARM3, a ZigBee wireless communication and μSD memory storage. With embedded algorithms it can detect in real time the postures of the subject. A preliminary assessment conducted on 12 subjects reached a 97% correct classification rate. The device exhibits 32 days of autonomy on a 3600 mAh capacity battery, which makes it convenient for field experiments in true daily life.

Objective evaluation of body displacements during activities using the wearable inertial system ActimedARM

“…8 days) on 3600 mAh battery (resp. 1200 mAh) [2]. When used as a data-logger, the embedded communication module is turned off to increase battery life allowing autonomy greater than 32 days (3600mAh).…”

“…The ActimedARM can measure the acceleration and the intensity of the magnetic field along its three axis and detect events (walking episodes, transfers, postures). It also performs a low-pass filtering on the acceleration data to remove highfrequency noise [2].…”

“…When used as a data-logger, the embedded communication module is turned off to increase battery life allowing autonomy greater than 32 days (3600mAh). The data are then written on the memory card for offline analysis [2].…”

“…We used a sensor we developed, the ActimedARM [2], to monitor activities (postures, transfer and walk) and wanted to use it for the objective assessment of the displacement during sit-to-stand tests.…”

Validation of Inverted Pendulum model for gait length calculation

“…ActimedARM is able to work in this mode more than 32 days continuously (with use of 3600mAh battery). [6] C. Experiment description In order to validate inverted pendulum model there were done the set of experiments. There were combined the proposed video system and ActimedARM devices.…”