David Friedman, Surjo Dutta MMA8451 Accelerometer David Friedman, Surjo Dutta

MMA8451 - Capabilities 3D acceleration measurements Tilt/orientation detection Jolt detection Pulse detection 8 - 14 bit resolution 99 micro-g noise level https://cdn-shop.adafruit.com/datasheets/MMA8451Q-1.pdf

Measurement capabilities Orientation detection Coarse grained detection of sensor orientation (+/- 30 degree uncertainty) 8 orientations detected: Portrait up or down front or back Landscape up and down Measurement capabilities Accelerations: 14 bit data for accelerations Ranges: +/- 2.00000 g +/- 4.0000 g +/- 8.000 g Jolt detection

Capacitive Accelerometers Acceleration generates spring motion of the proof mass. C1 and C2 are no longer equal. Voltages detected across C1 and C2 change. Capacitive Accelerometers MMA8451 is a capacitive accelerometer. In fact, it has three of them. One for each spatial direction. Sensing fingers Spring like structure Proof mass Acceleration C1 C2

Functionality Factory calibrated, but offsets can be manually set Can transmit 8 or 14 bit data through the I2C bus, for preference of speed or precision Auto Wake/Sleep can be triggered by an interrupt (Tap Detection, Orientation Detection and Motion/Freefall) “Freefall” or “Motion” detection allows the sensor to signal the processor of such an event. Thresholds for either event can be set by the user In-built tap detection and double tap detection with customizable pulse time width and latency between pulses Orientation detection, to switch between portrait and landscape Embedded Low-pass and High-pass filters, for noise reduction or to filter out slower data

References https://cdn-shop.adafruit.com/datasheets/MMA8451Q-1.pdf