ADXL3xx Accelerometer

This tutorial shows you how to read an Analog Devices ADXL3xx series (e.g. ADXL320, ADXL321, ADXL322, ADXL330) accelerometer and communicate the acceleration to the a personal computer through the serial monitor of the Arduino Software (IDE) or another application that receives data over the serial port.

This tutorial was built using the breakout boards from Sparkfun. The adafruit accelerometer breakout board also works, though it must be wired differently.

The ADXL3xx outputs the acceleration on each axis as an analog voltage between 0 and 5 volts. To read this, all you need is the analogRead() function.

Hardware Required

  • Arduino or Genuino Board
  • ADXL3xx Accelerometer


The accelerometer uses very little current, so it can be plugged into your board and run directly off of the output from the digital output pins. To do this, you'll use three of the analog input pins as digital I/O pins, for power and ground to the accelerometer, and for the self-test pin. You'll use the other three analog inputs to read the accelerometer's analog outputs.

image developed using Fritzing. For more circuit examples, see the Fritzing project page


click the image to enlarge

Here are the pin connections for the configuration shown above:

Breakout Board PinSelf-TestZ-AxisY-AxisX-AxisGroundVDD
Arduino Analog Input Pin012345

Or, if you're using just the accelerometer:

ADXL3xx PinSelf-TestZOutYOutXOutGroundVDD
Arduino PinNone (unconnected)Analog Input 1Analog Input 2Analog Input 3GND5V

Please, be aware that some accelerometers use 3.3V power supply and might be damaged by 5V. Check the supplier's documentation to find out which is the correct voltage.


The accelerometer connections are defined as constants at the beginning of the sketch, using the two Analog pins 4 and 5 as source of power. This is accomplished using them as Digital I/O pins 18 and 19. If needed, A0 is D14, A1 is D15 and so on.

const int groundpin = 18;
const int powerpin = 19;

Setting pin 19 (A5) as HIGH and pin 18 (A4) as LOW provides the 5V with few milliamps needed by the accelerometer to work.

pinMode(groundpin, OUTPUT);
pinMode(powerpin, OUTPUT);
digitalWrite(groundpin, LOW);
digitalWrite(powerpin, HIGH);

This solution allows the breakout boards from Sparkfun to be connected directly to your Arduino or Genuino board. Different boards may be connected to standard 5V - or 3.3V -and GND pins. In this latter case, the code may be amended commenting the lines above in the void setup() section.


 Reads an Analog Devices ADXL3xx accelerometer and communicates the
 acceleration to the computer.  The pins used are designed to be easily
 compatible with the breakout boards from Sparkfun, available from:

 The circuit:
 analog 0: accelerometer self test
 analog 1: z-axis
 analog 2: y-axis
 analog 3: x-axis
 analog 4: ground
 analog 5: vcc

 created 2 Jul 2008
 by David A. Mellis
 modified 30 Aug 2011
 by Tom Igoe

 This example code is in the public domain.


// these constants describe the pins. They won't change:
const int groundpin = 18;             // analog input pin 4 -- ground
const int powerpin = 19;              // analog input pin 5 -- voltage
const int xpin = A3;                  // x-axis of the accelerometer
const int ypin = A2;                  // y-axis
const int zpin = A1;                  // z-axis (only on 3-axis models)

void setup() {
  // initialize the serial communications:

  // Provide ground and power by using the analog inputs as normal
  // digital pins.  This makes it possible to directly connect the
  // breakout board to the Arduino.  If you use the normal 5V and
  // GND pins on the Arduino, you can remove these lines.
  pinMode(groundpin, OUTPUT);
  pinMode(powerpin, OUTPUT);
  digitalWrite(groundpin, LOW);
  digitalWrite(powerpin, HIGH);

void loop() {
  // print the sensor values:
  // print a tab between values:
  // print a tab between values:
  // delay before next reading:


Here are some accelerometer readings collected by positioning the y-axis of an ADXL322 2g accelerometer at various angles from ground. Values should be the same for the other axes, but will vary based on the sensitivity of the device. With the axis horizontal (i.e. parallel to ground or 0°), the accelerometer reading should be around 512, but values at other angles will be different for a different accelerometer (e.g. the ADXL302 5g one).



See Also:

Last revision 2015/07/28 by SM