PSN-L Email List Message

Subject: Re: ADXL202 Sensor
From: Karl Cunningham karlc@..........
Date: Thu, 24 May 2001 16:36:17 -0700

Hi Casey --

I'm curious just how much noise you do see.  Neglecting filters, sounds 
like you have a gain of 100 between the ADXL202 and your A/D.  How many 
counts of noise do you see on your A/D and how much voltage does one count 
represent?  Have you tried disconnecting the ADXL202 and shorting the input 
to the filter to see how much noise is produced without the sensor?

Karl Cunningham

--On Thursday, May 24, 2001 3:03 PM -0700 Casey Crane  

> Hello all,
>         I finally got finished building a two axis sensor using the
> ADXL202 accelerometer and boy, am I disapointed. I am using the analog
> outputs rather than the digital pwm outputs and the noise is tremendous.
> It is virtually a random noise generator ! I have the bandwidth for the
> ADXL202 chip set at 50 Hz along with a 12 Db
> 15Hz lowpass filter on the output then into a noninverting gain of
> 100 into my AtoD. Geez.... I have to literally shake the sensor to
> differentiate between the noise and the signal.
> I'll try a lower filter cutoff on the lopass and if that dose'nt work,
> I'm changing my allegiance to Lehman.


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Larry Cochrane <cochrane@..............>