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How to calibrate digital output accelerometers like ADXL345 or ADXL345 to obtain the outputs as 'g' values?

I have interfaced it with TM4C1294XL and the communication is through I2C protocol. Platform used is Energia.

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Don’t double post, it is bad etiquette. 

If you have a look at the datasheet you will see that the device is quite linear.  You can improve calibration by recording values at 1g and correcting for offset.  The datasheet also shows the influence of temperature. 

Also see https://learn.adafruit.com/adxl345-digital-accelerometer/programming

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I first posted on Embedded Systems/ Test equipment DEALS without realizing the word DEALS. Later I posted here and tried to delete the previous post but could not. Sorry for that.

On 5/5/2018 at 3:14 AM, Fmilburn said:

Don’t double post, it is bad etiquette. 

If you have a look at the datasheet you will see that the device is quite linear.  You can improve calibration by recording values at 1g and correcting for offset.  The datasheet also shows the influence of temperature. 

Also see https://learn.adafruit.com/adxl345-digital-accelerometer/programming

I calibrated it according to the datasheet where I found offset values for each axis and then subtracted it from the respective outputs. But I want outputs such that the parallel axis (to the ground) shows 0 (zero) g and perpendicular axis shows 9.8 g which I didn't get.

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Did you make a jig and follow the procedure in the Adafruit link?  What value are you seeing for g?  A value of 9.8 would be close for SI units.  However if it is reporting g-force the value should be close to 1.  I don’t have this sensor but cannot understand why a correction cannot be made if the sensor is giving relatively constant values at rest. 

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Yeah I followed the steps. But I didn't get either 9.8 or 1. There is formula online but that is not for digital output sensors like this. I somehow tried with that formula and I got values close to 1 but its not correct for all the axis. Still trying...

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