ADXL 345 数字式倾角传感器加速度模块

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产品简介

ADXL345小板是一个轻巧低功耗的3轴加速度计,具有高分辨率(13位)测量达到了±16g。可通过SPI(使用3或4根线)或I2C数字接口连接到开发板。在倾斜遥感应用中ADXL345非常适合静态测量重力的加速度以及动态加速运动或冲击造成的测量. 由于其高分辨率(4毫克/LSB)使测量倾角的变化不到1.0°都能测量。另外ADXL345还提供了一些特殊的传感功能。 活动和非活动检测功能通过比较任意轴上的加速度与用户设置的阈值来检测有无运动发生。敲击检测功能可以检测任意方向的单振和双振动作。自由落体检测功能可以检测器件是否正在掉落。这些功能可以独立映射到两个中断输出引脚中的一个。这些函数可以映射到两个中断输出插针之一。基于运动的智能电源管理,让带阈值检测功能和运动加速度测量功能以极低的功耗,低功耗模式运行。


ADXL345 1.jpgADXL345 2.jpg

规格参数

  • 接受2.0-3.6VDC直流电供电
  • 超低功耗:测量模式下电流为40 uA,2.5V 待机下为0.1uA
  • 单振/双振动监测
  • 自由落体检测
  • SPI或者I2C通信

应用示例

在这里我们用到ADXl345的SPI通信,将你的Arduino和ADXL335小板按照下面的方式接好线,将Adxl335的代码烧写进Arduino里面,然后打开Arduino的串口,观察到从adxl335传过来的数据。
ADXL Hookup.png

//Add the SPI library so we can communicate with the ADXL345 sensor
#include <SPI.h>

//Assign the Chip Select signal to pin 10.
int CS=10;

//This is a list of some of the registers available on the ADXL345.
//To learn more about these and the rest of the registers on the ADXL345, read the datasheet!
char POWER_CTL = 0x2D;	//Power Control Register
char DATA_FORMAT = 0x31;
char DATAX0 = 0x32;	//X-Axis Data 0
char DATAX1 = 0x33;	//X-Axis Data 1
char DATAY0 = 0x34;	//Y-Axis Data 0
char DATAY1 = 0x35;	//Y-Axis Data 1
char DATAZ0 = 0x36;	//Z-Axis Data 0
char DATAZ1 = 0x37;	//Z-Axis Data 1

//This buffer will hold values read from the ADXL345 registers.
char values[10];
//These variables will be used to hold the x,y and z axis accelerometer values.
int x,y,z;

void setup(){ 
  //Initiate an SPI communication instance.
  SPI.begin();
  //Configure the SPI connection for the ADXL345.
  SPI.setDataMode(SPI_MODE3);
  //Create a serial connection to display the data on the terminal.
  Serial.begin(9600);

  //Set up the Chip Select pin to be an output from the Arduino.
  pinMode(CS, OUTPUT);
  //Before communication starts, the Chip Select pin needs to be set high.
  digitalWrite(CS, HIGH);

  //Put the ADXL345 into +/- 4G range by writing the value 0x01 to the DATA_FORMAT register.
  writeRegister(DATA_FORMAT, 0x01);
  //Put the ADXL345 into Measurement Mode by writing 0x08 to the POWER_CTL register.
  writeRegister(POWER_CTL, 0x08);  //Measurement mode  
}

void loop(){
  //Reading 6 bytes of data starting at register DATAX0 will retrieve the x,y and z acceleration values from the ADXL345.
  //The results of the read operation will get stored to the values[] buffer.
  readRegister(DATAX0, 6, values);

  //The ADXL345 gives 10-bit acceleration values, but they are stored as bytes (8-bits). To get the full value, two bytes must be combined for each axis.
  //The X value is stored in values[0] and values[1].
  x = ((int)values[1]<<8)|(int)values[0];
  //The Y value is stored in values[2] and values[3].
  y = ((int)values[3]<<8)|(int)values[2];
  //The Z value is stored in values[4] and values[5].
  z = ((int)values[5]<<8)|(int)values[4];

  int yrotate=map(y,-150,150,0,180);
  //把绕X轴旋转180度的两个特定位置的yValue值195~525转换成角度值0~180
  int xrotate=map(x,-150,150,0,180);


  //Print the results to the terminal.
  Serial.print(xrotate);
  Serial.print(',');
  Serial.print(yrotate);
  Serial.print(',');
  Serial.println(z, DEC);      
  delay(200); 
}

//This function will write a value to a register on the ADXL345.
//Parameters:
//  char registerAddress - The register to write a value to
//  char value - The value to be written to the specified register.
void writeRegister(char registerAddress, char value){
  //Set Chip Select pin low to signal the beginning of an SPI packet.
  digitalWrite(CS, LOW);
  //Transfer the register address over SPI.
  SPI.transfer(registerAddress);
  //Transfer the desired register value over SPI.
  SPI.transfer(value);
  //Set the Chip Select pin high to signal the end of an SPI packet.
  digitalWrite(CS, HIGH);
}

//This function will read a certain number of registers starting from a specified address and store their values in a buffer.
//Parameters:
//  char registerAddress - The register addresse to start the read sequence from.
//  int numBytes - The number of registers that should be read.
//  char * values - A pointer to a buffer where the results of the operation should be stored.
void readRegister(char registerAddress, int numBytes, char * values){
  //Since we're performing a read operation, the most significant bit of the register address should be set.
  char address = 0x80 | registerAddress;
  //If we're doing a multi-byte read, bit 6 needs to be set as well.
  if(numBytes > 1)address = address | 0x40;

  //Set the Chip select pin low to start an SPI packet.
  digitalWrite(CS, LOW);
  //Transfer the starting register address that needs to be read.
  SPI.transfer(address);
  //Continue to read registers until we've read the number specified, storing the results to the input buffer.
  for(int i=0; i<numBytes; i++){
    values[i] = SPI.transfer(0x00);
  }
  //Set the Chips Select pin high to end the SPI packet.
  digitalWrite(CS, HIGH);
}

资源