I will take some photos and write up some details in a few days.
The idea was based on what I accidentally observed one day when
holding a flash light to the fuel tank. When the flash light is held
below the fuel level, the entire fluid lights up. When the flash light
is above the level, the tank lights up. The contrast across the fluid
level is about 10x. This is due to light being trapped above or below
the level. See attached pictures.
So, I made a board with four LEDs in a column, and another board with
10 photodetectors in a column. Using a microcontroller, I am flashing
each LED in sequence, and then computing the liquid level based on the
measured contrast. The output is displayed on a 10-bar display. The
LED board will attach to the aft of the baggage bay bulkhead, with
four holes to allow the light to get through. The detector board has
to attach somewhere on the front side of the tank. This might be the
tricky part because I need to make sure it is secure, but also
removable and does not interfere with the controls.
On Tue, Jun 17, 2014 at 5:52 AM, Kingsley Hurst
<kingsnjan@westnet.com.au> wrote:
> <kingsnjan@westnet.com.au>
>
> Andrew,
>
> What to do about a fuel gauge has been a bone of contention for me. I would
> very much appreciate your sharing how you made your device.
>
> Only thing is, can your set-up be accomplished AFTER the fuel tank and
> module are installed?
>
> Thanks
>
> Kingsley in Oz.
>
>
> -----Original Message----- From: Andrew Sarangan
> Sent: Tuesday, June 17, 2014 12:15 AM
> To: Europa List
> Subject: Europa-List: Noncontact fuel level indicator
>
>
> The fuel tank is translucent. One can clearly see the fuel level by
> eye. So, it occurred to me why not build a fuel level sensor that
> attaches to the outside of the tank? I recently built such a unit with
> LED illuminators and detectors, and it works like a charm. It even
> shows the waves when the fuel is sloshing around. Only question is,
> how does the translucency of the tank change with time? If it becomes
> totally opaque in a few years, then this won't work. I can post
> further details of the device if anyone is interested.
>
>
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