“(SKU:RB-02S037)ADXL345 三軸加速度計(jì)”的版本間的差異

2015年6月22日 (一) 15:16的版本

產(chǎn)品概述

ADXL345 數(shù)字三軸加速度計(jì)是一款小而薄的超低功耗3軸加速度計(jì)，分辨率高達(dá)(13位)，測(cè)量范圍達(dá)± 16g。數(shù)字輸出數(shù)據(jù)為16位二進(jìn)制補(bǔ)碼格式，可通過(guò)SPI(3線或4線)或I2C數(shù)字接口訪問(wèn)。ADXL345非常適合移動(dòng)設(shè)備應(yīng)用。它可以在傾斜檢測(cè)應(yīng)用中測(cè)量靜態(tài)重力加速度，還可以測(cè)量運(yùn)動(dòng)或沖擊導(dǎo)致的動(dòng)態(tài)加速度。其高分辨率(3.9mg/LSB)，能夠測(cè)量不到1.0°的傾斜角度變化。該器件提供多種特殊檢測(cè)功能?；顒?dòng)和非活動(dòng)檢測(cè)功能通過(guò)比較任意軸上的加速度與用戶(hù)設(shè)置的閾值來(lái)檢測(cè)有無(wú)運(yùn)動(dòng)發(fā)生。敲擊檢測(cè)功能可以檢測(cè)任意方向的單振和雙振動(dòng)作。自由落體檢測(cè)功能可以檢測(cè)器件是否正在掉落。這些功能可以獨(dú)立映射到兩個(gè)中斷輸出引腳中的一個(gè)。正在申請(qǐng)專(zhuān)利的集成式存儲(chǔ)器管理系統(tǒng)采用一個(gè)32級(jí)先進(jìn)先出(FIFO)緩沖器，可用于存儲(chǔ)數(shù)據(jù)，從而將主機(jī)處理器負(fù)荷降至最低，并降低整體系統(tǒng)功耗。低功耗模式支持基于運(yùn)動(dòng)的智能電源管理，從而以極低的功耗進(jìn)行閾值感測(cè)和運(yùn)動(dòng)加速度測(cè)量。

規(guī)格參數(shù)

1. 工作電壓：3.3-5v
2. 超低功耗：測(cè)量模式下40uA電流損耗，待機(jī)模式下0.1uA@2.5v
3. 通訊接口：I2C、SPI(3線or4線)
4. 接口類(lèi)型：0.1"插針孔

接線方法

例子程序

#include <Wire.h>
 
#define DEVICE (0x53)    //ADXL345 device address
#define TO_READ (6)        //num of bytes we are going to read each time (two bytes for each axis)
 
byte buff[TO_READ] ;    //6 bytes buffer for saving data read from the device
char str[512];                      //string buffer to transform data before sending it to the serial port
 
void setup()
{
  Wire.begin();        // join i2c bus (address optional for master)
  Serial.begin(9600);  // start serial for output
 
  //Turning on the ADXL345
  writeTo(DEVICE, 0x2D, 0);      
  writeTo(DEVICE, 0x2D, 16);
  writeTo(DEVICE, 0x2D, 8);
}
 
void loop()
{
  int regAddress = 0x32;    //first axis-acceleration-data register on the ADXL345
  int x, y, z;
 
  readFrom(DEVICE, regAddress, TO_READ, buff); //read the acceleration data from the ADXL345
 
  //each axis reading comes in 10 bit resolution, ie 2 bytes.  Least Significat Byte first!!
  //thus we are converting both bytes in to one int
  x = (((int)buff[1]) << 8) | buff[0];   
  y = (((int)buff[3])<< 8) | buff[2];
  z = (((int)buff[5]) << 8) | buff[4];
 
  //we send the x y z values as a string to the serial port
  sprintf(str, "%d %d %d", x, y, z);  
  Serial.print(str);
  Serial.write(10);
 
  //It appears that delay is needed in order not to clog the port
  delay(50);
}
 
//---------------- Functions
//Writes val to address register on device
void writeTo(int device, byte address, byte val) {
  Wire.beginTransmission(device); //start transmission to device 
  Wire.write(address);        // send register address
  Wire.write(val);        // send value to write
  Wire.endTransmission(); //end transmission
}
 
//reads num bytes starting from address register on device in to buff array
void readFrom(int device, byte address, int num, byte buff[]) {
  Wire.beginTransmission(device); //start transmission to device 
  Wire.write(address);        //sends address to read from
  Wire.endTransmission(); //end transmission
 
    Wire.beginTransmission(device); //start transmission to device
  Wire.requestFrom(device, num);    // request 6 bytes from device
 
  int i = 0;
  while(Wire.available())    //device may send less than requested (abnormal)
  { 
    buff[i] = Wire.read(); // receive a byte
    i++;
  }
  Wire.endTransmission(); //end transmission
}

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