ESP32 and MMA8452 accelerometer example

In this example we will connect a MMA8452Q accelerometer  to an ESP32 – in this case

Lets look at the sensor

The MMA8452Q is a smart, low-power, three-axis, capacitive, micromachined accelerometer with 12 bits of resolution. This accelerometer is packed with embedded functions with flexible user programmable options, configurable to two interrupt pins. Embedded interrupt functions allow for overall power savings relieving the host processor from continuously polling data.

The MMA8452Q has user selectable full scales of ±2 g/±4 g/±8 g with high-pass filtered data as well as non-filtered data available real-time. The device can be configured to generate inertial wakeup interrupt signals from any combination of the configurable embedded functions allowing the MMA8452Q to monitor events and remain in a low-power mode during periods of inactivity

Connection

Here is a layout, its an easy device to connect

esp32 and mma8452

Parts List

Here are the parts I used

Name	Link
ESP32		Aliexpress link Amazon Ebay
MMA8452		Aliexpress link Ebay link Amazon Link
Connecting cables		Aliexpress link Amazon Ebay

Code

This example does not require any libraries

// Distributed with a free-will license.
// Use it any way you want, profit or free, provided it fits in the licenses of its associated works.
// MMA8452Q
// This code is designed to work with the MMA8452Q_I2CS I2C Mini Module available from ControlEverything.com.
// https://www.controleverything.com/content/Accelorometer?sku=MMA8452Q_I2CS#tabs-0-product_tabset-2

#include <Wire.h>

// MMA8452Q I2C address is 0x1C(28)
#define Addr 0x1C

void setup()
{
  // Initialise I2C communication as MASTER
  Wire.begin();
  // Initialise Serial Communication, set baud rate = 9600
  Serial.begin(9600);

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select control register
  Wire.write(0x2A);
  // StandBy mode
  Wire.write((byte)0x00);
  // Stop I2C Transmission
  Wire.endTransmission();

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select control register
  Wire.write(0x2A);
  // Active mode
  Wire.write(0x01);
  // Stop I2C Transmission
  Wire.endTransmission();

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select control register
  Wire.write(0x0E);
  // Set range to +/- 2g
  Wire.write((byte)0x00);
  // Stop I2C Transmission
  Wire.endTransmission();
  delay(300);
}

void loop()
{
  unsigned int data[7];

  // Request 7 bytes of data
  Wire.requestFrom(Addr, 7);
  
  // Read 7 bytes of data
  // staus, xAccl lsb, xAccl msb, yAccl lsb, yAccl msb, zAccl lsb, zAccl msb
  if(Wire.available() == 7) 
  {
    data[0] = Wire.read();
    data[1] = Wire.read();
    data[2] = Wire.read();
    data[3] = Wire.read();
    data[4] = Wire.read();
    data[5] = Wire.read();
    data[6] = Wire.read();
  }

  // Convert the data to 12-bits
  int xAccl = ((data[1] * 256) + data[2]) / 16;
  if (xAccl > 2047)
  {
    xAccl -= 4096;
  }
    
  int yAccl = ((data[3] * 256) + data[4]) / 16;
  if (yAccl > 2047)
  {
    yAccl -= 4096;
  }
    
  int zAccl = ((data[5] * 256) + data[6]) / 16;
  if (zAccl > 2047)
  {
    zAccl -= 4096;
  }

  // Output data to serial monitor
  Serial.print("Acceleration in X-Axis : ");
  Serial.println(xAccl);
  Serial.print("Acceleration in Y-Axis : ");
  Serial.println(yAccl);
  Serial.print("Acceleration in Z-Axis : ");
  Serial.println(zAccl);
  delay(500);
}

Output

Open the serial monitor – this is what you should expect to see

Acceleration in X-Axis : -809
Acceleration in Y-Axis : -111
Acceleration in Z-Axis : 1508
Acceleration in X-Axis : -1696
Acceleration in Y-Axis : 346
Acceleration in Z-Axis : 1319
Acceleration in X-Axis : -458
Acceleration in Y-Axis : -851
Acceleration in Z-Axis : 2047
Acceleration in X-Axis : -31
Acceleration in Y-Axis : -813
Acceleration in Z-Axis : 2047
Acceleration in X-Axis : 235
Acceleration in Y-Axis : 46
Acceleration in Z-Axis : 1315

Links

https://www.nxp.com/docs/en/data-sheet/MMA8452Q.pdf