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Originally Posted by hello1990ab
I'm a rookie this year and playing with my teams accelerometer since we didnt use this year on the robot.
The IFI Site says that it returns 290 milivolts per g when supplied with 5volts (what I think the RC has).
How do the RC values 0-1023 reflect the g changes?
Also, when it says 2g, is that the same as 19.6 m/s^2?
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First of all, it's great that you are playing with the accelerometer, that's the best way to learn!
The RC measures between 0 and 5 volts at the Analog Inputs, returning values between 0 and 1023 (10 bits). So, a voltage of 2.5 volts would return 512. There is some tolerance there, plus or minus a few percent.
Also, the RC does have a +5v output, at the digital input pins.
Yes, 2g is the same as twice the acceleration due to gravity at sea level, or about 19.6 m/sec^2.
Please review the
specifications and data sheet carefully, and remember the range is +/- 2g, so the bias voltage (a constant voltage when the device is measuring 0 g) is about 1/2 the supply voltage, or perhaps 2.5 volts. That means, you'll measure 2.5 volts (512 on the RC) when both axes are perpendicular to the earth's gravity vector.
Luckily, you have a calibrated gravity field - point the sensor down to measure 1 g, up to measure -1 g, on both axes. Calibrate your RC that way, for + and - 1g in both the X and Y axes.
Good luck
Don