Memsic resolution

amirbaram

I've been using the memsic kit for a while and after changing the resistor from xOut
I am getting very small differences in signal length when memsic is facing forward or upward. I can see in debug that the memsic gives the same value as before when it is level, but when I tilt it all the way towards g or -g , I can see the change but it is very small. This still happens when I put back the old resistor (220 ohm).
Any suggestions?

Ryan Clarke

Amirbaram,

What values are you getting? What values did you 'swap out'?


Ryan

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Ryan Clarke
Parallax Tech Support

RClarke@Parallax.com

amirbaram

I tested t1 when laying flat would get 5.102 ms and 3.77 ms when parallal with g. Now I get 5.102ms when flat and 5.037 when parallal with g

Electronegativity

Hi amibaram:

I'm not familiar with the specific kit or accelerometer model you refer to, but typical Memsic accelerometers run at 100 Hz with a 50% duty cycle when lying flat, which gives a t1 value of 5 ms. For 20% deflection/g, and 10% tolerance, 3.77 ms when on its side is within spec.

It doesn't seem likely that changing the resistor would affect the accelerometer's output.


What you describe is exactly what I would expect if you tilted the accelerometer on the X axis, then read the value from the Y axis output.

Have you tried rotating it 90 degrees?

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I wonder if this wire is hot...