I have EVAL-ADXL345Z evaluation board from Analog Device hooked up to the Arduino UNO R3, the code complies and runs fine. At first I could still get the output values, but after sometime the output values i get is either 0 0 0 OR -1 -1 -1. Is it any problem with ADXL345 or Arduino UNO? Did I damage the sensor?
Connection:
ADXL345 --> Arduino
VIO --> 3.3V
GND --> GND
CS --> Pin 10
VS --> 3.3V
SCL --> Pin 13
SDA --> Pin 11
SDO --> Pin12
INT1 --> Pin 8
Code:
#include <SPI.h>
#define PINNUMBER
int CS=10;
char values[10];
int x,y,z;
double xg, yg, zg;
char ff=0;
long line = 0;
#define DEVID 0x00 //Device ID Register
#define OFSX 0x1E //X-axis offset
#define OFSY 0x1F //Y-axis offset
#define OFSZ 0x20 //Z-axis offset
#define THRESH_ACT 0x24 //Activity Threshold
#define THRESH_INACT 0x25 //Inactivity Threshold
#define TIME_INACT 0x26 //Inactivity Time
#define ACT_INACT_CTL 0x27 //Axis enable control for activity and inactivity detection
#define THRESH_FF 0x28 //free-fall threshold
#define TIME_FF 0x29 //Free-Fall Time
#define ACT_TAP_STATUS 0x2B //Source of tap/double tap
#define BW_RATE 0x2C //Data rate and power mode control
#define POWER_CTL 0x2D //Power Control Register
#define INT_ENABLE 0x2E //Interrupt Enable Control
#define INT_MAP 0x2F //Interrupt Mapping Control
#define INT_SOURCE 0x30 //Source of interrupts
#define DATA_FORMAT 0x31 //Data format control
#define DATAX0 0x32 //X-Axis Data 0
#define DATAX1 0x33 //X-Axis Data 1
#define DATAY0 0x34 //Y-Axis Data 0
#define DATAY1 0x35 //Y-Axis Data 1
#define DATAZ0 0x36 //Z-Axis Data 0
#define DATAZ1 0x37 //Z-Axis Data 1
void setup(){
SPI.begin();
SPI.setDataMode(SPI_MODE3); //configure accelerometer for SPI connecttion
Serial.begin(9600);
pinMode(CS, OUTPUT); //set chip select to be output
digitalWrite(CS, HIGH); //set chip select to be high
writeRegister(DATA_FORMAT, 0x03); //put accelerometer into 16G range
writeRegister(POWER_CTL, 0x08); //Measurement mode
}
void loop(){
readRegister(DATAX0, 6, values);
x = ((int)values[1]<<8)|(int)values[0];
y = ((int)values[3]<<8)|(int)values[2];
z = ((int)values[5]<<8)|(int)values[4];
line = line + 1;
Serial.print(line);
Serial.print('-');
Serial.print("X: ");
Serial.print(x, DEC);
Serial.print(',');
Serial.print("Y: ");
Serial.print(y, DEC);
Serial.print(',');
Serial.print("Z: ");
Serial.print(z, DEC);
Serial.print(',');
delay(100);
//convert accelerometer value to G
xg = x * 0.0078;
yg = y * 0.0078;
zg = z * 0.0078;
//Print the results to the terminal
//so that i can monitor the reading using the serial monitor.
Serial.print("xg: ");
Serial.print((float)xg,2);
Serial.print("g,");
Serial.print("yg: ");
Serial.print((float)yg,2);
Serial.print("g,");
Serial.print("zg: ");
Serial.print((float)zg,2);
Serial.println("g");
delay(100);
}
// 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); // to signal beginning of SPI packet
SPI.transfer(registerAddress);
SPI.transfer(value);
digitalWrite(CS, HIGH); // to signal end of SPI packet
}
void readRegister(char registerAddress, int numBytes, char * values){
// to perform read operation the most significant bit of the register address must be set
char address = 0x80 | registerAddress;
if(numBytes > 1)address = address | 0x40;
digitalWrite(CS, LOW);
SPI.transfer(address);
for(int i=0; i<numBytes; i++){
values = SPI.transfer(0x00);
}
digitalWrite(CS, HIGH);
}
Best Answer
Does it start out OK, but degrade over time? Or did it work once, but now fails every time?
A ggogle search found this pdf, with handling considerations on the first page:
1. Not reverse polarity protected
2. Dropping on a hard surface can exceed Acceleration limits.
The main other options for breaking the sensor would be: static damage, or the Arduino IO exceeding 3.3V. The Data sheet here lists a voltage limit of 3.9V (page 6).
According to the UNO web page, the "official" output levels are 5V...
Does the R3 version have logic level translation? Did you use some form of voltage divider? Have you got a modified board, like discussed here?