SEN-12803 Datasheet SEN-12803 | P1-P3

ADXL337 and ADXL377 Accelerometer

Hookup Guide

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Introduction

The ADXL337 and the ADXL377 are both small, thin, low power, complete

3-axis accelerometers with signal conditioned analog voltage outputs.

Here are photographs of each accelerometer breakout board which we

created to make these small chips easier to use:

The primary difference between the two is the range of acceleration they

measure. The ADXL337 measures acceleration with a full-scale range of ±3

g while the ADXL377 has a full-scale range of ±200 g for measuring more

extreme changes in motion, shock or vibration.

Covered in this Tutorial

In this tutorial, we will help you learn how to use these accelerometers so

you can quickly and painlessly integrate them into your project[s]. Here is

what we’ll cover:

• Hardware Overview – An overview of the ADXL337/ADXL377 IC’s,

and their respective breakout boards we designed to make them

simple to use.

• Example Hookup – How to connect the accelerometers to the

ubiquitous Arduino so we can start writing code to work with them.

• Example Code – We’ve written example sketches that demonstrate

how to collect sensor data as well as make sense of it.

Required Materials

• ADXL337 Breakout Board and/or ADXL377 Breakout Board

• Arduino Uno or any Arduino Board– We will use the Uno as the

example, however you should be able to use any Arduino board you

have handy including the RedBoard, Pro, Mega, etc.

You may also need a breadboard, jumper wires, and straight male headers

to follow the example setup, if you don’t already have these or another way

of connecting the Arduino to the breakout board.

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Suggested Readin

Before continuing on with this tutorial, we recommend you be somewhat

familiar with the concepts in these tutorials:

• Accelerometer Basics – This is a great primer on accelerometers –

how they work, and why they’re used.

• Accelerometer Buying Guide – If you’re not sure which

accelerometer is best for you, check out this guide.

• Logic Levels – The ADXL337/ADXL377 are 3.3V devices, so your

analog to digital (ADC) readings will vary depending on whether

you’re using a 5V or 3.3V micro! Both will work, just be aware of how

it affects the values the microcontroller reads.

Hardware Overview

The Breakout Boards for the ADXL337 and ADXL377 break out the all the

pins you’ll need to get the necessary data from the accelerometers.

As you can see, each breakout has the same pins broken out. Here is

some information about each pin:

Label

Pin Function Input/OutputNotes

3.3V Power Supply Input Can be between 1.8 - 3.6V.

X axis

acceleration

Output

Analog output whose voltage

correlates to acceleration measured on

the X axis

Y axis

acceleration

Output

Analog output whose voltage

correlates to acceleration measured on

the Y axis

Z axis

acceleration

Output

Analog output whose voltage

correlates to acceleration measured on

the Z axis

ST Self Test Input Used to verify sensor functionality

GND Ground Input

0V, common voltage to share with

microcontroller circuit

Voltage Supply Requirements

The big alert here is that the ADXL337 and ADXL377 both have a

maximum voltage of 3.6V – that range applies to both the power supply

and the self test pin. You can use a 5V or 3.3V micro with these sensors as

long as you power the board with 3.3V. Be aware though, that your analog

to digital (ADC) readings will vary depending on whether you’re using a 5V

or 3.3V micro! Both will work, just be aware of how it affects the numeric

values the microcontroller reads.

Fortunately, you don’t need a lot of power to make the accelerometers

work. In normal operating mode they typically draw about 300µA.

Extra Hardware Notes

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If you are powering either the ADXL337 or ADXL377 with 3.3V, a voltage

reading of 1.65V on the X pin will correspond to an acceleration reading of

0g for both chips. However, if the X pin reads 3.3V, on the ADXL337 this

means a force of 3g is being applied on the x axis while the same reading

on an ADXL377 would indicated a force of 200g. The usage of both chips is

essentially the same, but interpreting the readings is different due to the

scale that each chip measures.

The ADXL377 also has 4 mounting holes, as opposed to just two, to allow

for a more secure physical connection to your project since it will likely be

subjected to more extreme force.

Also, for both chips, 0.01µF capacitors are used on the X, Y, and Z outputs.

This means the maximum rate you can collect acceleration data from the

IC’s is 500Hz.

Example Hookup

Soldering

Before you can plug your accelerometer breakout board into a breadboard

and connect it to anything, you’ll need to solder connectors or wires to the

breakout pins. What you solder to the board depends on how you’re going

to use it.

If you’re going to use the breakout board in a breadboard or similar

0.1"-spaced perfboard, we recommend soldering straight male headers into

the pins (there are also long headers if you need).

If you’re going to mount the breakout into a tight enclosure, you may want

to solder wires (stranded or solid-core) directly into the pins.

Simple Hookup

This example will use an Arduino Uno to collect and interpret the sensor

data from the ADXL337 or ADXL377. Since the sensors' outputs are

analog, all we need are three wires between the Arduino’s ‘Analog In’ pins

and accelerometer (aside from power and ground). While the following

hookup diagram shows the ADXL337, the header and connections to the

Arduino are the same for both boards. Here’s the hookup:

We simply have to supply the accelerometer with power (3.3V and GND),

then hookup the X, Y, and Z lines of the sensor to ADC pins (A0, A1, and

A2 respectively in this case). The self test pin (ST) can be left disconnected

or connected to ground under normal operation. If you want to use the self

test to double check the functionality of the sensor, tie it to 3.3V. Check the

datasheet for more info.

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P1-P3 P4-P6

SEN-12803

Mfr. #:

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Manufacturer:

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Description:

Acceleration Sensor Development Tools Triple Axis Accelerometer

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