LIS2DH12 as movement sensor when the device can be oriented in any way, not just flat/parallel

[terminator_pro]

I would like LIS2DH12 to fire Interrupt1 (to wake up the microcontroller) when the device is slightly moved. I have it working if the device/LIS2DH12 is laying flat parallel to the ground, moving it slightly fires the Interrupt. However, if the device the laying at a angle like 30 degrees, moving it slightly does not fire the Interrupt1. Is this not supported or somehow I need to specify the "rest state" so the movement can be compare to it? I am using Arduino IDE.

One example of code is attached below that only works if the device is laying flat initially. I have tried other examples with same results. I am not tied to a particular library. Please provide some arduino code that work!

#include <Wire.h>
#include "SparkFun_LIS2DH12.h"

SPARKFUN_LIS2DH12 accel;

int accelInterruptPin = 27;

void setup()
{
  Serial.begin(115200);
  delay(500);
  Serial.println("SparkFun Accel Example");

  Wire.begin();

  if (!accel.begin())
  {
    Serial.println("Accelerometer not detected. Check address jumper and wiring. Freezing...");
    while (1);
  }

  pinMode(accelInterruptPin, INPUT_PULLUP);

  accel.setDataRate(LIS2DH12_POWER_DOWN); //Stop measurements

  // Set INT_POLARITY to Active Low
  accel.setIntPolarity(LOW);

  // Set INT1 interrupt
  accel.setInt1IA1(true);

  // Set INT1 threshold and duration for any movement detection
  accel.setInt1Threshold(6); // Set threshold to the smallest value for any movement
  accel.setInt1Duration(9);  // Set a duration to filter out noise

  // Clear the interrupt
  while (accel.getInt1()) delay(10); // Reading int will clear it

  // Set data rate and enable interrupts
  accel.setDataRate(LIS2DH12_ODR_400Hz); 
  accel.setInt1(true); // Enable interrupts on INT1 pin

  Serial.println("Begin Interrupt Scanning");
  Serial.println("Detecting any movement...");
}

void loop()
{
  // Poll for the interrupt via I2C just for testing purposes 
  if (accel.getInt1() == true) // Reading int will clear it
  {
    Serial.print(millis());
    Serial.println(" Movement Detected!");
  }

  delay(100);
}

[AScha.3]

So its up to you, to detect movement on "enabled axes" - depends on how you setup the chip.

Maybe the lib you use, can be set to it, as you like - just try it. (Or look in the lib, how its working and adjust it to your target.)

+

>Please provide some arduino code that work!

For this you should ask in Arduino Forum !

[terminator_pro]

Thank you for the quick response. The detection is enabled on all x,y,z axis. Let me rephrase the question and I don't see this any of the examples - is it possible to setup INT1 in a way where if the device starts off on a 30 degree angle and then moved slightly, the INT1 is triggered? If so, can you point me to an example in anything that you have?

I can get it to work if the device is flat/parallel to the ground, moving it in x, y or z slightly triggers INT1 but if starts out not flat to the ground then I can't get it to work. How does it know what the "rest" state is and moving it from the rest state should trigger INT1? - default of 0 makes sense but if the device is at an angle to start with, it won't be zero - is there a way to set this? For example, imagine this is in ball and the ball can be left in any orientation, then when the ball is slightly moved, INT1 should trigger. 

[Federica Bossi]

Hi @terminator_pro ,

You can refer to AN5005, at page 26, it is reported that before configuring your desired wake-up event on INT1, a dummy read of the REFERENCE register is performed to set the current/reference acceleration/tilt state against which the device performed the threshold comparison.