[Gal Longin]

Originally Posted by Chris Hibner

I need to add one thing:

When you sit the accelerometer flat on the table (NOT aligned with gravity), the A/D reading (in counts) is the zero G reading of the accelerometer. You should subtract this zero-G reading from your other readings before applying the conversion factor that I mentioned above.

For example:

on the table you see that the average is 705. This is 0 G's

let's say your accelerometer gain (also called accelerometer sensitivity) is 200 mV/G

Therefore, your conversion factor is 1 count = (5000 mV/1024 coutns) * (1 G / 200 mV)

Thus, 1 count = 0.024414 G (or 1 G = 40.96 counts).

Now, turn the accelerometer so that it is aligned with gravity. Your new reading should be approximately 746 A/D counts (i.e. 705 + 41 = 746)


For another example, let's say you put the accelerometer at the edge of a centrifuge and you want to see what the acceleration is at the edge of the centrifuge. The accelerometer reads 923 (after averaging out the noise). How many G's is that?

923 - 705 = 218 counts of acceleration.

1 G = 40.96 counts, so 218 counts = 218 counts * 1G / 40.96 counts

218 counts = 5.322 G's

Therefore, you see 5.322 G's at the edge of the centrifuge.

Thanks for your help.