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Topic: Accelerometer allows only low sample rate? (Read 549 times) previous topic - next topic

larsw2

Hi

I'm using a standard Arduino Uno board and connected an accelerometer (ADXL335). I measure voltages on the analog pins in the loop function and this goes on forever, no processing. However, the frame rate I get is 1700/s.

Can that be right? I was hoping for a frame rate 10 times as large, if not higher? Am I doing anything wrong?

Lars

AWOL

Using analogRead, the most I'd expect would be one read every 100us or so, (about 9600 samples per second), so over three channels an update rate of 3200 per second (without any other processing or I/O).
If you need a higher rate, you'd have to use an external A/D converter, but this would seem to me to be a bit pointless, because the maximum bandwidth of the device is only around 1500Hz.
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liudr

Using the accelerometer at this rate is not recommended. You'll pick up something like vibrations (if the board doesn't already have a capacitor to filter them out). What was your purpose of such a high sampling rate?

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