Accéléromètre ADXL355 (industrial grade)

On a rotating machine, the signature of an incipient bearing fault appears as lines of a few tens of milli-g, buried in noise. What decides detectability is the sensor's noise floor: at 22,5 µg/√Hz (±2 g), the ADXL355 sits an order of magnitude lower than a general-purpose accelerometer such as the MPU6050 (~400 µg/√Hz). Its 20-bit output and bandwidth up to 1 kHz cover the classic fault frequencies (BPFO/BPFI, gear meshing) with enough dynamic range for FFT. Its response down to DC also allows tracking of tilt or slow imbalance.

Honest limits: the usable band tops out at 1 kHz — insufficient for very-high-frequency gear defects or cavitation ultrasound, where an IEPE piezo (10–20 kHz) remains superior. The ±8 g range confines its use to vibration, not violent shocks. For cheap, coarse screening, the ADXL345 or the MPU6050 are enough; the ADXL355 is justified when the goal is reliable spectral analysis, not a simple threshold alarm.