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Originally Posted by KenWittlief
if you have the eval board version, the output signal is already filtered with a cuttoff around 40Hz.
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I know that. However, the datasheet for the evaluation board states that "the user may add an external capacitor to further reduce the bandwidth and improve the noise floor." I was just curious as to whether anyone would recommend doing that.
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Originally Posted by KenWittlief
Question I gotta ask? what sort of angular rate test fixture are you using to produce a steady yaw rate while you monitor the output?
if you are holding the eval board in your hand and twisting your wrist back and forth, then the strange waveform you are seeing is exactly what your wrist is doing.
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I was indeed using my hand to rotate the device. However, the waveform generated was more regular and of a higher frequency than anything I suspect my hand would be capable of inducing.
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Originally Posted by KenWittlief
I did the same thing with ours - same device - the signal was all over the place when I turned it in my hand.
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That's very reassuring. That part was expensive enough that the thought of having to replace it was not a pleasant one. I'll try it out with a more stable testbed.
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Originally Posted by KenWittlief
We mounted it on our bot, closed the loop, and our bot tracks the sensor signal just beautifully - we are adding the signal to an accumulator to create a compass heading, and to steer closed loop we do the same thing with the signal from the X axis of the driver joystick - we divide it by 2, then add it to an accumulator.
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That is a remarkably cool idea. We're using a trapezoidal integration algorithm to generate a similar absolute heading value. The data from that is being used concurrently with the second integral of the output of a Motorola MMA1201P accelerometer and a few trigonometric lookup tables to allow us to determine the robot's longitudinal and latitudinal deviation (in feet) from its starting location.