Introduction; Specifications And Functionality Of The Wgt3X-Bt; Data; Acceleration - ActiGraph wGT3X-BT User Manual

Introduction

The wGT3X-BT activity monitors provide objective measurements of human activity and are used in
many research and clinical applications. They include a microelectromechanical system (MEMS) based
accelerometer, ambient light, and a touch sensor as data collection end points. No formal training is
required to use the wGT3X-BT device and patients may be the intended operator. This document will
serve as the only necessary training guide needed to get full functionality from the device.

Specifications and Functionality of the wGT3X-BT

Data

The devices include both an acceleration sensor as well as an ambient light sensor. Data will not be
negatively affected by lint, dust, or direct sunlight.

Acceleration

The devices include an acceleration sensor that consists of a microelectromechanical systems (MEMS)
accelerometer yielding the following product specifications:
The acceleration data is stored at rates ranging from 30 Hz to 100 Hz (user selectable) and stored in a
raw, non-filtered/accumulated format in the units of gravity (g's). This data is stored directly into a non-
volatile flash memory. The accelerometer is very sensitive and is accurate within +/- 0.5% of the data
collected.

Ambient Light

Ambient light data is sampled and stored to memory at a 1 Hz rate. When a downloaded data file is
converted into an accumulated *.agd format with epoch lengths greater than one second, the lux values
for that epoch are averaged. An estimate of lux values is shown in Table 1.
49 E. Chase St.
Parameter
Axis
Sensitivity
Dynamic Range
Table 1 – Accelerometer Key Specifications
Lux Level
1
50
Pensacola, FL 32502
Value Units
3
4 mg/LSB
+/- 8 g
Interpretation Comparison
Twilight
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