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Vibration Detection Using FXOS8700CQ

Question asked by walidbalid on Apr 19, 2016
Latest reply on May 7, 2016 by walidbalid



I have observed some strange behavior when using FXOS8700CQ in the hybrid mode running at 400KHz. The Acelorometer signal is noisy (noise mean is around 200>please see figure 1) and transient spikes with high amplitude are observed (please see figure 2 and 3) without causing any movement or Vibrations!


In brief, I would use the Accelorometer sensor to detect the vertical acceleration on a surface, caused by a car passing adjacent to the sensor, which is fixed to the surface. In such case, what would be the best configuration for the accelerometer? What is the reason for these transient spikes?


The configuration I set for the sensor is as follows:

Fxos8700cq_mag_ctrl_reg1_adr = B00011111

Fxos8700cq_mag_ctrl_reg2_adr = B00100000

Fxos8700cq_xyz_data_cfg = B00000000

Fxos8700cq_sys_ctrl_reg3_adr = B00000000

Fxos8700cq_sys_ctrl_reg4_adr = B00000001

Fxos8700cq_sys_ctrl_reg5_adr = B00000001

Fxos8700cq_m_vecm_cfg = B01111110

Fxos8700cq_m_vecm_ths_msb = B10000000

Fxos8700cq_m_vecm_ths_lsb = 70

Fxos8700cq_m_vecm_cnt = 2