AVR-Chat

The company I mentioned earlier makes two sensors types.  One trips on  
wet and the other actually needs real water, not just moisture  
sticking to the walls of the container.


On Jan 13, 2009, at 7:19 PM, Tim Gilbert wrote:

> Most windshield rain sensors use the index of refraction principle;  
> however, the difference between "full" and "just wet" isn't very much.
>
> Tim Gilbert
> JEM Innovation Inc.
> 303-926-9053 (office)
> 303-437-4342 (cell)
> 720-890-8582 (fax)
> www.jeminnovation.com
> www.pdksolutions.com
>
>  ----- Original Message -----
>  From: Robert Tilden
>  To: AVR-Chat@yahoogroups.com
>  Sent: Tuesday, January 13, 2009 8:14 PM
>  Subject: RE: [AVR-Chat] Liquid level measurement
>
>
>  Perhaps an IR reflection sensor on the outside. There may be enough  
> of a
>  difference in index of refraction between air and liquid on the  
> inside that
>  there will be a reflection from the air/plastic interface when  
> empty and no
>  reflection when full. If you can use separate emitters/sensors you  
> could
>  adjust the angle of incidence to optimize the signal difference.
>
>  Capacitance sensing would work as well, but would need more  
> circuitry.
>
>  -----------------------------------
>  Bob Tilden, tilden@northwestern.edu
>  High Energy Physics Group
>  Northwestern University
>
>  -----Original Message-----
>  From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On  
> Behalf
>  Of Enki
>  Sent: Tuesday, January 13, 2009 7:44 PM
>  To: AVR-Chat@yahoogroups.com
>  Subject: [AVR-Chat] Liquid level measurement
>
>  I need to measure the liquid level inside a transparent plastic
>  bottle. I need to know when the liquid is below half bottle height  
> and
>  when the bottle is almost empty. Just two steps.
>  The plastic bottle measures 12cm high x 8cm x 3cm.
>  I'm not allowed to insert any probe in the bottle.
>  There are four bottles side by side.
>
>  I was thinking on metal plates mounted on each side of each bottle
>  and using the capacitance method.
>
>  Or a B&W video camera and some processing. I could generate four
>  sample windows on each video line and integrate the samples. The four
>  integrated signals would represent the liquid level on each bottle.
>  An ATMEGA48 would do the level measurement with four ADCs.
>
>  Comments, please.
>
>  Thanks,
>  Mark Jordan
>
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