0

I get the following output from serial monitor when trying to use the ADXL345 with Arduino Uno in SPI mode (I2C mode works fine):

CA
Ooops, no ADXL345 detected ... Check your wiring!

See photos for wiring. I have tried it with another breakout board, and that produces the same results. Interestingly this tutorial says the breakout should work in SPI mode, but it's only illustrated for I2C. https://learn.adafruit.com/adxl345-digital-accelerometer?view=all#assembly-and-wiring

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL345_U.h>    
/* Assign a unique ID to this sensor at the same time */
Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(13,12,11,9);
//Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified();

//Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(clock,miso,mosi,cs,sensorID);
void displaySensorDetails(void)
{
  sensor_t sensor;
  accel.getSensor(&sensor);
  Serial.println("------------------------------------");
  Serial.print  ("Sensor:       "); Serial.println(sensor.name);
  Serial.print  ("Driver Ver:   "); Serial.println(sensor.version);
  Serial.print  ("Unique ID:    "); Serial.println(sensor.sensor_id);
  Serial.print  ("Max Value:    "); Serial.print(sensor.max_value); Serial.println(" m/s^2");
  Serial.print  ("Min Value:    "); Serial.print(sensor.min_value); Serial.println(" m/s^2");
  Serial.print  ("Resolution:   "); Serial.print(sensor.resolution); Serial.println(" m/s^2"); 
  Serial.println("------------------------------------");
  Serial.println("");
  delay(500);
}

void displayDataRate(void)
{
  Serial.print  ("Data Rate:    ");

  switch(accel.getDataRate())
  {
    case ADXL345_DATARATE_3200_HZ:
      Serial.print  ("3200 ");
      break;
    case ADXL345_DATARATE_1600_HZ:
      Serial.print  ("1600 ");
      break;
    case ADXL345_DATARATE_800_HZ:
      Serial.print  ("800 ");
      break;
    case ADXL345_DATARATE_400_HZ:
      Serial.print  ("400 ");
      break;
    case ADXL345_DATARATE_200_HZ:
      Serial.print  ("200 ");
      break;
    case ADXL345_DATARATE_100_HZ:
      Serial.print  ("100 ");
      break;
    case ADXL345_DATARATE_50_HZ:
      Serial.print  ("50 ");
      break;
    case ADXL345_DATARATE_25_HZ:
      Serial.print  ("25 ");
      break;
    case ADXL345_DATARATE_12_5_HZ:
      Serial.print  ("12.5 ");
      break;
    case ADXL345_DATARATE_6_25HZ:
      Serial.print  ("6.25 ");
      break;
    case ADXL345_DATARATE_3_13_HZ:
      Serial.print  ("3.13 ");
      break;
    case ADXL345_DATARATE_1_56_HZ:
      Serial.print  ("1.56 ");
      break;
    case ADXL345_DATARATE_0_78_HZ:
      Serial.print  ("0.78 ");
      break;
    case ADXL345_DATARATE_0_39_HZ:
      Serial.print  ("0.39 ");
      break;
    case ADXL345_DATARATE_0_20_HZ:
      Serial.print  ("0.20 ");
      break;
    case ADXL345_DATARATE_0_10_HZ:
      Serial.print  ("0.10 ");
      break;
    default:
      Serial.print  ("???? ");
      break;
  } 
  Serial.println(" Hz"); 
}

void displayRange(void)
{
  Serial.print  ("Range:         +/- ");

  switch(accel.getRange())
  {
    case ADXL345_RANGE_16_G:
      Serial.print  ("16 ");
      break;
    case ADXL345_RANGE_8_G:
      Serial.print  ("8 ");
      break;
    case ADXL345_RANGE_4_G:
      Serial.print  ("4 ");
      break;
    case ADXL345_RANGE_2_G:
      Serial.print  ("2 ");
      break;
    default:
      Serial.print  ("?? ");
      break;
  } 
  Serial.println(" g"); 
}

void setup(void)
{
#ifndef ESP8266
  while (!Serial); // for Leonardo/Micro/Zero
#endif
  Serial.begin(9600);
  Serial.println("Accelerometer Test"); Serial.println("");
  pinMode(9,OUTPUT);
  /* Initialise the sensor */
  if(!accel.begin())
  {
    /* There was a problem detecting the ADXL345 ... check your connections */
    Serial.println("Ooops, no ADXL345 detected ... Check your wiring!");
    while(1);
  }

  /* Set the range to whatever is appropriate for your project */
  accel.setRange(ADXL345_RANGE_16_G);
  // displaySetRange(ADXL345_RANGE_8_G);
  // displaySetRange(ADXL345_RANGE_4_G);
  // displaySetRange(ADXL345_RANGE_2_G);

  /* Display some basic information on this sensor */
  displaySensorDetails();

  /* Display additional settings (outside the scope of sensor_t) */
  displayDataRate();
  displayRange();
  Serial.println("");
}

void loop(void)
{
  /* Get a new sensor event */
  sensors_event_t event;
  accel.getEvent(&event);

  /* Display the results (acceleration is measured in m/s^2) */
  Serial.print("X: "); Serial.print(event.acceleration.x); Serial.print("  ");
  Serial.print("Y: "); Serial.print(event.acceleration.y); Serial.print("  ");
  Serial.print("Z: "); Serial.print(event.acceleration.z); Serial.print("  ");Serial.println("m/s^2 ");
//  delay(500);
}

enter image description here

0

I got it to work using the Sparkfun library in stead of the Adafruit library, and by inserting a couple of delay(100) statements in the setup (without them the output was continuously -13365, -13365, -13365). I still don't fully understand why the delay statements would be necessary in the first place though.

/*  ********************************************* 
 *  SparkFun_ADXL345_Example
 *  Triple Axis Accelerometer Breakout - ADXL345 
 *  Hook Up Guide Example 
 *  
 *  Utilizing Sparkfun's ADXL345 Library
 *  Bildr ADXL345 source file modified to support 
 *  both I2C and SPI Communication
 *  
 *  E.Robert @ SparkFun Electronics
 *  Created: Jul 13, 2016
 *  Updated: Sep 06, 2016
 *  
 *  Development Environment Specifics:
 *  Arduino 1.6.11
 *  
 *  Hardware Specifications:
 *  SparkFun ADXL345
 *  Arduino Uno
 *  *********************************************/

#include <SparkFun_ADXL345.h>         // SparkFun ADXL345 Library

/*********** COMMUNICATION SELECTION ***********/
/*    Comment Out The One You Are Not Using    */
ADXL345 adxl = ADXL345(9);           // USE FOR SPI COMMUNICATION, ADXL345(CS_PIN);
//ADXL345 adxl = ADXL345();             // USE FOR I2C COMMUNICATION

/****************** INTERRUPT ******************/
/*      Uncomment If Attaching Interrupt       */
//int interruptPin = 2;                 // Setup pin 2 to be the interrupt pin (for most Arduino Boards)


/******************** SETUP ********************/
/*          Configure ADXL345 Settings         */
void setup(){

  Serial.begin(9600);                 // Start the serial terminal
  Serial.println("SparkFun ADXL345 Accelerometer Hook Up Guide Example");
  Serial.println();

  adxl.powerOn();                     // Power on the ADXL345
  delay(100); 
  adxl.setRangeSetting(16);           // Give the range settings
                                      // Accepted values are 2g, 4g, 8g or 16g
                                      // Higher Values = Wider Measurement Range
                                      // Lower Values = Greater Sensitivity
  delay(100); 
  adxl.setSpiBit(0);                  // Configure the device to be in 4 wire SPI mode when set to '0' or 3 wire SPI mode when set to 1
                                      // Default: Set to 1
                                      // SPI pins on the ATMega328: 11, 12 and 13 as reference in SPI Library 
  delay(100); 
//  Set SPI mode to that matching ADXL345 (I guess this would be in here by default? ) 

  adxl.setActivityXYZ(1, 0, 0);       // Set to activate movement detection in the axes "adxl.setActivityXYZ(X, Y, Z);" (1 == ON, 0 == OFF)
  adxl.setActivityThreshold(75);      // 62.5mg per increment   // Set activity   // Inactivity thresholds (0-255)

  adxl.setInactivityXYZ(1, 0, 0);     // Set to detect inactivity in all the axes "adxl.setInactivityXYZ(X, Y, Z);" (1 == ON, 0 == OFF)
  adxl.setInactivityThreshold(75);    // 62.5mg per increment   // Set inactivity // Inactivity thresholds (0-255)
  adxl.setTimeInactivity(10);         // How many seconds of no activity is inactive?

  adxl.setTapDetectionOnXYZ(0, 0, 1); // Detect taps in the directions turned ON "adxl.setTapDetectionOnX(X, Y, Z);" (1 == ON, 0 == OFF)

  // Set values for what is considered a TAP and what is a DOUBLE TAP (0-255)
  adxl.setTapThreshold(50);           // 62.5 mg per increment
  adxl.setTapDuration(15);            // 625 μs per increment
  adxl.setDoubleTapLatency(80);       // 1.25 ms per increment
  adxl.setDoubleTapWindow(200);       // 1.25 ms per increment

  // Set values for what is considered FREE FALL (0-255)
  adxl.setFreeFallThreshold(7);       // (5 - 9) recommended - 62.5mg per increment
  adxl.setFreeFallDuration(30);       // (20 - 70) recommended - 5ms per increment

  // Setting all interupts to take place on INT1 pin
  //adxl.setImportantInterruptMapping(1, 1, 1, 1, 1);     // Sets "adxl.setEveryInterruptMapping(single tap, double tap, free fall, activity, inactivity);" 
                                                        // Accepts only 1 or 2 values for pins INT1 and INT2. This chooses the pin on the ADXL345 to use for Interrupts.
                                                        // This library may have a problem using INT2 pin. Default to INT1 pin.

  // Turn on Interrupts for each mode (1 == ON, 0 == OFF)
  adxl.InactivityINT(1);
  adxl.ActivityINT(1);
  adxl.FreeFallINT(1);
  adxl.doubleTapINT(1);
  adxl.singleTapINT(1);

//attachInterrupt(digitalPinToInterrupt(interruptPin), ADXL_ISR, RISING);   // Attach Interrupt

}

/****************** MAIN CODE ******************/
/*     Accelerometer Readings and Interrupt    */
void loop(){

  // Accelerometer Readings
  int x,y,z;   
  adxl.readAccel(&x, &y, &z);         // Read the accelerometer values and store them in variables declared above x,y,z

  // Output Results to Serial
  /* UNCOMMENT TO VIEW X Y Z ACCELEROMETER VALUES */  
  Serial.print(x);
  Serial.print(", ");
  Serial.print(y);
  Serial.print(", ");
  Serial.println(z); 

//  ADXL_ISR();
  // You may also choose to avoid using interrupts and simply run the functions within ADXL_ISR(); 
  //  and place it within the loop instead.  
  // This may come in handy when it doesn't matter when the action occurs. 

}

/********************* ISR *********************/
/* Look for Interrupts and Triggered Action    */
void ADXL_ISR() {

  // getInterruptSource clears all triggered actions after returning value
  // Do not call again until you need to recheck for triggered actions
  byte interrupts = adxl.getInterruptSource();

  // Free Fall Detection
  if(adxl.triggered(interrupts, ADXL345_FREE_FALL)){
    Serial.println("*** FREE FALL ***");
    //add code here to do when free fall is sensed
  } 

  // Inactivity
  if(adxl.triggered(interrupts, ADXL345_INACTIVITY)){
    Serial.println("*** INACTIVITY ***");
     //add code here to do when inactivity is sensed
  }

  // Activity
  if(adxl.triggered(interrupts, ADXL345_ACTIVITY)){
    Serial.println("*** ACTIVITY ***"); 
     //add code here to do when activity is sensed
  }

  // Double Tap Detection
  if(adxl.triggered(interrupts, ADXL345_DOUBLE_TAP)){
    Serial.println("*** DOUBLE TAP ***");
     //add code here to do when a 2X tap is sensed
  }

  // Tap Detection
  if(adxl.triggered(interrupts, ADXL345_SINGLE_TAP)){
    Serial.println("*** TAP ***");
     //add code here to do when a tap is sensed
  } 
}

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.