Go Down

Topic: Stuck on calibration for (LSM303) Accelerometer (Read 2 times) previous topic - next topic

gdavisiv

The closest I could get the Y Value was to -1 when i point it to North

Accel X: 16 Y: 52 Z: 1052
Mag X: 278 Y: -1 Z: -203

When I turn it -180 degree's (South) it goes up to -180.  Is it safe to assume the Y-axis will give me my reading of North?

Accel X: -20 Y: 44 Z: 1056
Mag X: -249 Y: -180 Z: -185

Thanks!

jjspierx

Sounds like it, are the results repeatable?  If so, I would guess the orientation of the sensor is such that the y-axis is your heading axis.  It is Z for mine. 

gdavisiv

Yes they are repeatable I just copied one instance.  Awesome! Thanks for your help one problem solved.


Back to my original question how do I tell if the readings I'm getting for the Accelerometer are 1. correct, 2. how do i translate them into something usable? or are they already usable?

Chagrin

The acceleration due to gravity is pretty constant  8) so when you've got it sitting still in any position you know the value it's reporting is 9.8 m/s2. The datasheet for the chip states it is factory calibrated so there shouldn't be any second guessing required.

The magnetometer is a different problem since it will see interference from any number of wires or traces running around it. When you complete your project you would need to calibrate it in situ by rotating it full circle and checking its readings at a chosen number of points.

gdavisiv


The acceleration due to gravity is pretty constant  8) so when you've got it sitting still in any position you know the value it's reporting is 9.8 m/s2. The datasheet for the chip states it is factory calibrated so there shouldn't be any second guessing required.


I'll be honest I attempted to read the datasheet but a lot of it seemed like jibberish to me.. I'll read it again and at least try to find the part you mentioned so I know for next time.. anything else I should know? A friend of mine suggested I look into "Azmuth equations?"

Go Up