3-AXIS ACCELEROMETER ADXL-345

                      
 INTRODUCTION
  

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 twos complement and is accessible through either a SPI (3- or 4-wire) or I2C digital interface. The ADXL345 is well suited for mobile device applications. It measures 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 measurement of inclination changes less than 1.0°. Several special sensing functions are provided. Activity and inactivity sensing detect the presence or lack of motion and if the acceleration on any axis exceeds a user-set level. Tap sensing detects single and double taps. Free-fall sensing detects if the device is falling. These functions can be mapped to one of two interrupt output pins. An integrated, patent pending 32-level first in, first out (FIFO) buffer can be used to store data to minimize host processor intervention. Low power modes enable intelligent motion based power management with threshold sensing and active acceleration measurement at extremely low power dissipation.

FEATURES

• Ultralow power: as low as 40µA in measurement mode and µA in stand by mode.
• Power consumption scales automatically with bandwidth user selectable resolution.
• Embedded, patent pending FIFO technology minimizes host processor load tap/double tap detection.
• Activity/inactivity monitoring.
• Free fall detection.
• SPI and I2C digital interfaces.

•  Measurement ranges selectable via serial command.
• Bandwidth selectable via serial command.
• Pb free/RoHS compliant.
• 10,000g shock survival

APPLICATIONS

• Handsets.
• Medical instrumentation.
• Gaming and pointing devices

PIN DETAIL

 

SPECIFICATIONS

WORKING

The ADXL345 is a complete 3-axis acceleration measurement system with a selectable measurement range of ±2 g, ±4 g, ±8 g, or ±16 g. It measures both dynamic acceleration resulting from motion or shock and static acceleration, such as gravity, that allows the device to be used as a tilt sensor. The sensor is a poly silicon surface-micro machined structure built on top of a silicon wafer. Poly silicon springs suspend the structure over the surface of the wafer and provide a resistance against forces due to applied acceleration. Deflection of the structure is measured using differential capacitors that consist of independent fixed plates and plates attached to the moving mass. Acceleration deflects the proof mass and unbalances the differential capacitor, resulting in a sensor output whose amplitude is proportional to acceleration. Phase-sensitive demodulation is used to determine the magnitude and polarity of the acceleration. Power can be applied to VS or VDD I/O in any sequence without damaging the ADXL345. The interface voltage level is set with the interface supply voltage, VDD I/O, which must be present to ensure that the ADXL345 does not create a conflict on the communication bus. For single-supply operation, VDD I/O can be the same as the main supply, VS. In a dual-supply application, however, VDD I/O can differ from VS to accommodate the desired interface voltage, as long as VS is greater than or equal to VDD I/O. After VS is applied, the device enters standby mode, where power consumption is minimized and the device waits for VDD I/O to be applied and for the command to enter measurement mode to be received. In addition, while the device is in standby mode, any register can be written to or read from to configure the part. It is  recommended to configure the device in standby mode and then to enable measurement mode. Clearing the measure bit returns the device to the standby mode.

 

 

 

 

Micro SD Memory Card interface for 3.3V MCU

OVERVIEW:

This is a wonderful little SD card interface module. It is easily interfaced as a peripheral to your module. Through programming, you can read and write to the SD card.All SD Card works on 3V interface so if your microcontroller is working on 3V you can use this board readily. The interface board provided is for microcontrollers running at 3V.

FEATURES:

• This SD Card module can make your SD application more easier and simple.
• It is easily interfaced as a peripheral to your module.
• Through programming, you can read and write to the SD card.
• Can be used for SD Card more eaisly, such as for MP3 Player, MCU/ARM system control.
• All SD SPI pins output, MOSI, SCK, MISO and CS.
• Support 3.3V input.
• High quality PCB FR4 Grade with FPT Certified.

APPLICATIONS:

 

• MP3 player.
• MCU/Arm system control.

SPECIFICATIONS:

CIRCUIT DIAGRAM:

ARDUINO CODE:
/*
* Project name:
Micro SD Memory Card interface for 3.3V MCU
* Copyright
(c) Researchdesignlab.com
* Description:
* Test configuration:
MCU: ATMEGA328
Dev.Board: Arduino uno
Oscillator: 16 MHz
Software: Arduino
*/
/*
/*
SD card read/write

This example shows how to read and write data to and from an SD card file
The circuit:
* SD card attached to SPI bus as follows:
** MOSI - pin 11
** MISO - pin 12
** CLK - pin 13
** CS - pin 4

created Nov 2010
by David A. Mellis
modified 9 Apr 2012
by Tom Igoe

This example code is in the public domain.

*/

#include <SD.h>
File myFile;
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect.
}

Serial.print("Initializing SD card...");
// On the Ethernet Shield, CS is pin 4. It's set as an output by default.
// Note that even if it's not used as the CS pin, the hardware SS pin
// (10 on most Arduino boards, 53 on the Mega) must be left as an output
// or the SD library functions will not work.
pinMode(10, OUTPUT);

if (!SD.begin(4)) {
Serial.println("initialization failed!");
return;
}
Serial.println("initialization done.");

// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
myFile = SD.open("test.txt", FILE_WRITE);

// if the file opened okay, write to it:
if (myFile) {
Serial.print("Writing to test.txt...");
myFile.println("testing 1, 2, 3.");
// close the file:
myFile.close();
Serial.println("done.");
} else {
// if the file didn't open, print an error:
Serial.println("error opening test.txt");
}

// re-open the file for reading:
myFile = SD.open("test.txt");
if (myFile) {
Serial.println("test.txt:");

// read from the file until there's nothing else in it:
while (myFile.available()) {
Serial.write(myFile.read());
}
// close the file:
myFile.close();
} else {
// if the file didn't open, print an error:
Serial.println("error opening test.txt");
}
}
void loop()
{
// nothing happens after setup
}




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