www.theactigraph.com
P a g e
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7
49 E. Chase St. Pensacola, FL 32502 tel 850.332-7900 fax 850-332-7904
Introduction
The wGT3X+ and wAc 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 and an ambient light as data sensors.
Specifications and Functionality of the wGT3X+ and wAc
Data
The devices include both an acceleration sensor as well as an ambient light sensor.
Acceleration
The devices include an acceleration sensor that consists of a microelectromechanical systems (MEMS)
accelerometer yielding the following product specifications:
Parameter
Value
Units
Axis
3
Sensitivity
220
mV/g
Dynamic Range
+/- 6
G
Table 1 – Accelerometer Key Specifications
The acceleration data is sampled by a 12 bit analog to digital converter 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 256 or 512 MB non-volatile flash memory.
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.
Lux Level
Interpretation Comparison
1
Twilight
50
Family living room
100
Very dark overcast day
320-500
Office lighting
