Very nice sensor (I would go the paralled 'dipstick' tube route) - thx for
the link! I could not find any compatibility tables and wonder if any of
the nasties (are there chlorinated solvents?) in auto fuel are a problem.
I guess the key to Andrew's eloquent solution of actually using the tank as
the optical refractor is that there is no fuel contact with any sensors,
nor any additional plumbing required.
Cheers & thx,
Pete
On Tue, Jun 17, 2014 at 11:07 AM, Nigel Graham <nigel_graham@m-tecque.co.uk>
wrote:
> I did a similar thing some years back when building an alloy tank. I used
> a series of solid-state liquid level sensors (data sheet attached) that
> incorporate a photo diode and photo transistor moulded into a polysulphone
> housing. The domed end uses the simple effect of total internal reflection
> to either switch the transistor on or off depending on whether it is
> immersed or not.
> I mounted mine in tapped bosses on the surface of the tank, but these
> could easily be built into a "dip-stick" and mounted from the top of the
> plastic tank. Just another variation on a theme.
>
> Nigel
>
>
> On 17/06/2014 15:02, Andrew Sarangan wrote:
>
>> 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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