There are two types of accelerometer you can get, DC coupled and AC coupled. I haven't looked into it but the Bangle likely has a DC coupled accelerometer and these types measure the acceleration due to gravity. An AC coupled accelerometer is what is used for forced vibration tests and they won't measure low frequency acceleration such as gravity only the higher frequency dynamic acceleration.
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There are two types of accelerometer you can get, DC coupled and AC coupled. I haven't looked into it but the Bangle likely has a DC coupled accelerometer and these types measure the acceleration due to gravity. An AC coupled accelerometer is what is used for forced vibration tests and they won't measure low frequency acceleration such as gravity only the higher frequency dynamic acceleration.