View source for Digital Accelerometer ADXL345 Module

=='''Introduction'''==
[[File:adxl345.png]]<br>
<P>The ADXL345 is a small, thin, low power, 3-axis accelerometer with high resolution (13-bit) measurement at up to ±16 g. Digital output data is formatted as 16-bit two’s complement and is accessible through either an SPI (3- or 4-wire) or I2C digital interface.<br> 
The ADXL345 is well suited to measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion or shock. Its high resolution (4 mg/LSB) enables the inclination change measurement by less than 1.0°. And the excellent sensitivity (3.9mg/LSB @2g) provides a high-precision output of up to ±16g.<br>  
In this experiment, I2C digital interface is used.<br> 
See the following figure for the schematic diagram. There is a 3.3v voltage regulator chip in the circuit, so you can power the module with 5V or 3.3V.<br>
ADXL345 works like this:<br>  
[[File:zuobiao2.png]]<br>
When you place the module face up, Z_OUT is at the maximum which is +1g; face down, Z_OUT is at the minimum. No matter of face, as long as it's placed on a level surface, X_OUT increases along the Ax axis direction, so does Y_OUT along the Ay axis. See the picture below. Thus, when you rotate the module, you can see the changes of X_OUT, Y_OUT, and Z_OUT.
[[File:zuobiao.png]]<br></P>

=='''Features'''==
<p>
Ultra low power: 25 to 130 µA at VS = 2.5 V (typ)<br>
Power consumption scales automatically with bandwidth<br>
User selectable fixed 10-bit resolution or 4mg/LSB scale<br>
factor in all g-ranges, up to 13-bit resolution at ±16 g<br>
32 level output data FIFO minimizes host processor load<br>
Built in motion detection functions<br>
• Tap/Double Tap detection<br>
• Activity/Inactivity monitoring<br>
• Free-Fall detection<br>
Supply and I/O voltage range: 1.8 V to 3.6 V<br>
SPI (3 and 4 wire) and I2C digital interfaces<br>
Flexible interrupt modes – Any interrupt mappable to either<br>
interrupt pin<br>
Measurement ranges selectable via serial command<br>
Bandwidth selectable via serial command<br>
Wide temperature range (-40 to +85°C)<br>
10,000 g shock survival<br>
Pb free/RoHS compliant<br>
Small and thin: 3 × 5 × 1 mm LGA package</p>

=='''Schematic'''==
[[File:ADXL345 ad.png]]<br>
=='''Test'''==
==='''To use the ADXL345 with Arduino, you can take the following steps. '''===
 '''Step1:'''Connecting circuit 
    It can share the I2C bus with other I2C devices as long as each device has a unique address. Only 4 connections are required for I2C communication.<br>
:::::::ADXL345       -------     Arduino Uno/Mega2560
:::::::: GND         ---------         GND
::::::::3.3V         -------            3.3V
:::::::: SCL          -------          A5 Uno/pin21 Mega2560
:::::::: SDA          -------          A4 Uno/pin20 Mega2560
[[File:ADXL345_bb.png]]<br>
 '''Step2:''' Upload the code
 #include <Wire.h>  
 #define Register_ID 0
 #define Register_2D 0x2D
 #define Register_X0 0x32
 #define Register_X1 0x33
 #define Register_Y0 0x34
 #define Register_Y1 0x35
 #define Register_Z0 0x36
 #define Register_Z1 0x37
 int ADXAddress = 0x53;  //I2C address
 int reading = 0;
 int val = 0;
 int X0,X1,X_out;
 int Y0,Y1,Y_out;
 int Z1,Z0,Z_out;
 double Xg,Yg,Zg;
 
 void setup()
 {
   Serial.begin(9600);//设置串行通信率为9600
   delay(100);
   Wire.begin();  //初始化I2C
   delay(100);
   Wire.beginTransmission(ADXAddress);
   Wire.write(Register_2D);
   Wire.write(8);
   Wire.endTransmission();
   Serial.println("Accelerometer Test ");
 } 
 void loop()
 {
   Wire.beginTransmission(ADXAddress);
   Wire.write(Register_X0);
   Wire.write(Register_X1);
   Wire.endTransmission();
   Wire.requestFrom(ADXAddress,2);
   if(Wire.available()<=2);
   {
     X0 = Wire.read();
     X1 = Wire.read();
     X1 = X1<<8;
     X_out = X0+X1;
   } 
   Wire.beginTransmission(ADXAddress);
   Wire.write(Register_Y0);
   Wire.write(Register_Y1);
   Wire.endTransmission();
   Wire.requestFrom(ADXAddress,2);
   if(Wire.available()<=2);
   {
     Y0 = Wire.read();
     Y1 = Wire.read();
     Y1 = Y1<<8;
     Y_out = Y0+Y1;
   } 
   Wire.beginTransmission(ADXAddress);
   Wire.write(Register_Z0);
   Wire.write(Register_Z1);
   Wire.endTransmission();
   Wire.requestFrom(ADXAddress,2);
   if(Wire.available()<=2);
   {
     Z0 = Wire.read();
     Z1 = Wire.read();
     Z1 = Z1<<8;
     Z_out = Z0+Z1;
   } 
   Xg = X_out/256.00;//把输出结果转换为重力加速度g,精确到小数点后2位。
   Yg = Y_out/256.00;
   Zg = Z_out/256.00;
   Serial.print("X=");
   Serial.print(Xg);
   Serial.print("\tY=");
   Serial.print(Yg);
   Serial.print("\tZ=");
   Serial.println(Zg);
   delay(300);  //延时0.3秒，刷新频率这里进行调整 
 }

 '''Step3:''' Select correct Board and Port

 '''Step4:''' Upload the sketch to the SunFounder Uno board
    After uploading, open Serial Monitor, where you can see the data detected. When the acceleration of the module changes, the figure will change accordingly on the window.<br>
[[File:adxl xinaxiang.jpg]]<br>

=='''Resource'''==
[http://wiki.sunfounder.cc/images/4/45/ADXL345datasheet.pdf ADXL345datasheet][[File:PDF.jpg]]<br>
[https://www.sunfounder.com/learn/Super_Kit_V3_0_for_Raspberry_Pi/lesson-17-adxl345-super-kit-v3-0-for-raspberry-pi.html Test Experiment for Raspberry Pi][[File:LINK.jpg]]