Newsgroups: comp.robotics
Path: brunix!sgiblab!zaphod.mps.ohio-state.edu!moe.ksu.ksu.edu!osuunx.ucc.okstate.edu!olesun!gcouger
From: gcouger@olesun.okstate.edu (Gordon Couger)
Subject: Re: Bubble Level
Message-ID: <1993Apr25.171112.23631@osuunx.ucc.okstate.edu>
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References: <1993Apr25.103920.7688@reed.edu>
Date: Sun, 25 Apr 1993 17:11:12 GMT
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In article <1993Apr25.103920.7688@reed.edu> reeder@reed.edu (P. Douglas Reeder) writes:
>My question is: what dark fluid should I use?  I'd like to
>use something other than ink or oil, because the sensor
>might leak.
>
You might get by by using plain water and infered LED there is one wavelength
of IR that is highly attenuated by water.

>Also, will refractive effects cause weird problems when the
>end of the buble is between a pair?  Will I get a monotonic
>increase in transmissivity as the bubble moves between a
>pair?
a
When the end of the bubble crosses in front of the sensor you will get
a very marked decrease in the light going to the sensor. At least I did
when I built a water level sensor for a robot. I pumped water into a beaker
and watched for a sharp drop in the light. Worked well except when a drop
splashed up and blocked the sensor. The beaker when full of water acted as
a lens showing a great increase in light as it was moved by the dector array.

Good luck 
Gordon

>
>-- 
>Doug Reeder                              Internet: reeder@reed.edu
>Div, Grad & Curl                         USENET:   ...!tektronix!reed!reeder
>programming & derivative work 
>I am actively seeking scientific programming contracts.


Gordon Couger 
Agriculture Engineering Oklahoma State University
114 Ag Hall, Stillwater, OK  74074
gcouger@olesun.agen.okstate.edu 405-744-9763 day 624-2855 evenings  
