ActiGraph wGT3X-BT - Steps; Inclinometer; Inclinometer Definitions

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49 E. Chase St. Pensacola, FL 32502 tel 850.332-7900 fax 850-332-7904
100
Very dark overcast day
320-500
Office lighting
400
Sunrise/sunset
1,000
Overcast day
10,000-25,000
Full daylight
32,000-130,000
Direct sunlight
Table 1 – Lux Level Interpretation Estimates
Steps
Step counts are accumulated on a per-epoch basis and are based on accelerometer data collected on
the vertical axis. An algorithm present in the device firmware filters out the accelerometer’s baseline
noise level to help accurately accumulate the steps-per-epoch.
Inclinometer
The inclinometer feature can help users identify the orientation of the device and, more importantly,
when the device itself was taken off. Each epoch is flagged with a number (1 through 4) to indicate the
orientation of the device during that epoch. For wGT3X-BT devices, this is done within the ActiLife
software when converting the *.gt3x file to *.agd format. As noted, the inclinometer feature is only
valid when the device is worn vertically on the point of the hip. More details are available in the
Inclinometer Whitepaper.
Important The inclinometer feature is only valid if the device is worn on the hip
with Axis 1 upward facing.
Inclinometer Code
(Stored with each Epoch)
Interpretation
0
Device Off (Not Being Worn)
1
Subject Standing
2
Subject Lying Horizontal
3
Subject Sitting
Table 3 - Inclinometer Definitions