ADXL345 false interrupt

Projects General Guidance
1

I have an ADXL345 accelerometer integrated into a PCB, but it's triggering false activity interrupts approximately 4/5 times per hour.

I placed the PCB on a table for 24 hours, during which there was absolutely no movement, but I received 100+ interrupts within that time frame. Any suggestions or insights into what might be causing this issue would be greatly appreciated.

adxl
adxl704×396 14.5 KB

datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/adxl345.pdf

//TURN ADXL ON 
    Wire.beginTransmission(ADXL345_ADDRESS);
    Wire.write(0x2D);
    Wire.write(0x08);  // Set to normal operation mode    00001000 (0x08)
    Wire.endTransmission();
 



//adxl settup
  Wire.beginTransmission(ADXL345_ADDRESS);
  Wire.write(0x2C);  // SET power mode + data rate HZ
  Wire.write(0x04);  // Set data rate to 0.78 Hz.      (0000 0100) normal power + data rateHZ
  Wire.endTransmission();
 
  //ENABLE ACTIVITY detection
  Wire.beginTransmission(ADXL345_ADDRESS);
  Wire.write(0x27);  // enable control for activity detection 
  Wire.write(0xF0);  //  0xF0 = 11110000   //ENABLE ACTIVITY: ac,x,y,z  disable inactivity: ac/dc,x,y,z
  Wire.endTransmission();

  //  INT_1 / INT_2
  Wire.beginTransmission(ADXL345_ADDRESS);
  Wire.write(0x2F);  //  Interrupt mapping control INT1 or INT2  EF=INT1:activity  
  Wire.write(0x00);
  Wire.endTransmission();

  // Interrupt enable for ACTIVITY
  Wire.beginTransmission(ADXL345_ADDRESS);  // 0x10= activity ON (00010000) all other off(OFF: freefall,inactivity,tap...)
  Wire.write(0x2E);
  Wire.write(0x10);  // Enable just activity
  Wire.endTransmission();

  //Activity threshold
  Wire.beginTransmission(ADXL345_ADDRESS);
  Wire.write(0x24);
  Wire.write(0x08);  //  0-255 deimal  00000000-11111111     62.5mg * 255 =15,937mg(16g)  0x07=every_6min_false   0x09=1hr_no_false
  Wire.endTransmission();

then i use this code to get interrupts

attachInterrupt(digitalPinToInterrupt(GPIO_adxl345), adxl345_new_motionISR, RISING);

2

Check up the power supply as well as the electrical environment and other devices connected to the controller.

Snippets of code is not advised in the link: How to get the best out of this forum - Using Arduino / IDE 1.x - Arduino Forum

3

Too little information provided. Specify MCU, post all the code, a complete wiring diagram, etc.

Especially with I2C, avoid long, loose wires, as they pick up electrical noise leading to read errors.

4

interrupt has nothing to do with i2c here. from adxl345 interrupt pin it goes directly to esp32 pin , and when interrupt pin gets high , esp32 digital read it and report that there is moovement

5

No such connection was suggested or implied. However, avoid long, loose wires.

6

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