Home Sensors MMA8451 accelerometer

MMA8451 accelerometer

by iainhendry

The MMA8451 is a low-power, three-axis capacitive accelerometer with 14 bits of resolution, featuring:

  • Embedded functions with flexible user-programmable options, configurable to two interrupt pins
  • Embedded interrupt functions for overall power savings relieving the host processor from continuously polling data
  • Access to both low-pass filtered data as well as high-pass filtered data, which minimizes the data analysis required for jolt detection and faster transitions
  • Inertial wake-up interrupt signals from any combination of the configurable embedded functions allowing the MMA8451Q to monitor events and remain in a low-power mode during periods of inactivity



  • 1.95 to 3.6-volt supply voltage
  • 1.6 to 3.6-volt interface voltage
  • ±2g/±4g/±8g dynamically selectable full-scale
  • Output data rates (ODR) from 1.56 Hz to 800 Hz
  • 99 μg/√Hz noise
  • 14-bit and 8-bit digital output
  • I²C digital output interface (operates to 2.25 MHz with 4.7 kΩ pull-up)
  • Two programmable interrupt pins for seven interrupt sources
  • Three embedded channels of motion detection
    • Freefall or motion detection: one channel
    • Pulse detection: one channel
    • Jolt detection: one channel
  • Orientation (portrait/landscape) detection with programmable hysteresis
  • Automatic ODR change for auto-wake and return to sleep
  • 32 sample FIFO
  • High pass filter data available per sample and through the FIFO
  • Self-test



Of course as you have seen earlier the sensor is quite tricky to work with for the hobbyist, luckily there are a few ready made modules out there to make things easier, here is one of them which breaks ou all the required connections to a header



These are the schematics of the module above


Sample Connection

This shows how you would connect the module above to an Arduino Uno, being an I2C device it is relatively easy. Similar connections for other development boards but you may want to use the 3.3v power rather than Vin.




For an Arduino I recommend the https://github.com/adafruit/Adafruit_MMA8451_Library/archive/master.zip the examples are easy to follow, I alway s recommend looking at the code ion the library as well, its interesting to see how it all works.

For any MBed related development boards there is the https://developer.mbed.org/users/emilmont/code/MMA8451Q/ library



Datasheet : http://www.nxp.com/files/sensors/doc/data_sheet/MMA8451Q.pdf

The module is low cost and can easily be purchased for under $3

GY-45 MMA8451 Modules Digital Triaxial Accelerometer

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