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LIS3DH - Motion and crash detection

Question asked by Arek Arkowski on Feb 26, 2018
Latest reply on Apr 17, 2018 by Miroslav B

Hello all

 

My goal is to use two INT pins to generate two interrupts in a device which will be used in a car. INT2 will be pulled when a crash of the car is detected and INT1 when the car moves.

Here is my init setting:

 

CTRL_REG1 = 0x27 //10Hz, normal power mode, ZXY enable

CTRL_REG2 = 0x01 // HP filter for INT1

CTRL_REG3 = 0x40 //IA1 enable

CTRL_REG4 = 0x90 //4g | BDU

CTRL_REG5 = 0x0A //latch on INT1 and INT2

CTRL_REG6 = 0x22 //active low & INT2 enable

INT2_THS     = 0x6D //~3500mg

INT2_DURATION = 0x00 // 0.1*0s 

INT2_CFG     = 0x2A  //OR, X,Y,Z higher than threshold

INT1_THS     = 0x02 //

INT1_DURATION = 0x03 //

INT1_CFG    = 0x2A //

 

Generally, the motion detection part works fine (thanks to Miroslav). I am concerned about the crash detection part.The threshold is quite high (I don't want it to interrupt on every bump on the road) but it still sometimes interrupts when no hight acceleration is applied. It is very rare but still occurs. 

 

If you have any inputs to this I'll appreciate.

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