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ADXLxxx Accelerometers Configuration

Question asked by alvjorge on Apr 2, 2013
Latest reply on Apr 10, 2013 by neilzhao

Hi,

 

I have three models of Analog accelerometers (ADXL312, ADXL345 & ADXL362).

 

After reading their data sheets, I'm starting to work with them, and I have several questions I need to solve to achieve their right behaviour for my application.

 

First, I'm going to explain my application and the goals I want to get.

  • The accelerometers need to be installed in a portable hardware platform managed by a MCU, wich reads data from accelerometers.
  • MCU have to be asleep the most time possible. Only waking up when accelerometers make an interruption because of a higher vibration than the threshold level preprogrammed.
  • These vibrations are low level ones, also their frequency are low. Between 1 to 100 Hz.
  • Moreover, they have to work in low or ultra-low power mode (as 362 can do), to avoid unnecessary consumption.

 

So, here there goes my questions:

  1. Which are the most important parameter I have to modify to get the higher sensitivity from the accelerometers?? I'll explain better the question. I know sensitivity/scale factor are similar but is there any more factors to make more sensitive these devices (ODR, resolution...).
  2. How can they get the minimun vibrations levels?? Which is measurement range is the most sensitive?? (1.5g, ..., 16g)
  3. To work in low/ultra-low power mode, I need more info about. I don't have too much clear how I have to configure them for their right behaviour (reduce the power consumption without avoid getting measurements). Which are the registers I have to manage and how??
  4. I read about work with activity and inactivity interruptions in low power mode, and duration register. This could be a great solution for me, but my problem is that I don't know the real values I have to measure for the moment. The values gives back in the examples are in g's??
  5. One last question, about offset and gains, how are they affecting to measurement and how I can configure to better measurements?

 

I hope you can understand everything, but if something is not clear enough, ask me please, and I'll try to explain it better.

 

Thanks in advance!

 

Regards,

Jorge

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