Fuel Tank level????

[ngeronikolos]

Hello and good morning from the Strike ATHENS,

I would like your experience accoring a fuel leveler.
I have a RC (hoddy) Car which has a fuel tank 75cc(look at the attached photo).I want to measure any time the level of my fuel.
How I can do it????
What sensor I should use???Note that the tank is very small.


Last but not list, I am looking for small LCDs (40mm x 16mm could be great for my project).Where I can find????
Are there 3vdc LCDs???

Please advice
Nikos

[flotulopex]

Have a look here for LCDs http://www.lcd-module.de/

[ardhuru]

I feel a capacitive sensor would be the best way to go. You could fabricate one yourself; check out the pdf on this page http://www.capsense.com/technology.htm

Regards,

Anand

[earltyso]

I have had great luck with all of the crystalfonz LCD products.
try them out
www.crystalfontz.com

[ngeronikolos]

ardhuru,

I do not have any experience on capacitive liquid level sensors.Does anyone has???
Please give it to me with simple words.

Nikos

[skimask]

I do not have any experience on capacitive liquid level sensors.Does anyone has???
Please give it to me with simple words.

There are no really simple words...
A capacitor is made up of 2 plates, separated by a dielectric material. When a capacitor holds 'capacitance', it has an electrostatic field on it, limited by a number of factors (plate area, plate material, dielectric material and constant, blah blah blah). You can look it all up in Wikipedia...

Anywho's....a capacitive liquid level sensor uses the fuel in the tank to change the dielectric constant of the dielectric material, thereby changing the total capacitance of the probes.
In aircraft, one of the ways to measure this is to measure the phase change between a reference sine wave and a sine wave that has been passed thru the capacitor. Higher cap's, bigger phase change. Another way is to 'measure' AC current flow thru a variable impedance (variable impedance here being the capacitor X(c) = 1 / (2 x PI x Freq x C ).

[JD123]

Simple...

A capacitor is two conductive surfaces and a dielectric between them. The dielectric can be air, water, acid or most anything that is mechanically compatible. The dielectric doesn’t even have to be in contact with the surfaces. The dielectric is going to react to the field of voltage potential between the two conductors. The closer to the conductors and the larger the area of the conductors combined with the dielectric’s properties give you a capacitance vale. Some dielectrics work better than others. In this case, the fuel is the better dielectric than the air inside the tank. More fuel, more area of dielectric, the higher the capacitance. Lower capacitance for lower fuel levels.

Placing two metal surfaces on the OUTSIDE of the tank (window-alarm tape works great) with a very small vertical space (the two strips go up and down on the side of the tank) creates a capacitor. When fuel is added and more of the area of the metal strips is covered with fuel, the higher the capacitance value. The capacitance can be read on a PIC using POT command (read up on it). The PBP manual shows the capacitor part of the equation. There are other ways to do this too, but effectively what you are doing will be to check the R-C time decay constant with the PIC. Keep in mind that the capacitance range and values will be very small. Getting the hardware values right will be the hardest part.

Oh, I’m sorry… you a said simple explanation… two vertical metal strips placed close together on the side (outside) of the fuel tank (PLASTIC TANK). Use this for the capacitor value in the POT PBP command.

Check the web for examples to get you in the ballpark. I've seen and read about this before, but I can't remember where right now.

[ngeronikolos]

Thanks thanks thanks

I have to read a lot about it and test it...

JD123, what is it the window-alarm tape???

Nikos

[skimask]

Simple...
Oh, I’m sorry… you a said simple explanation… two vertical metal strips placed close together on the side (outside) of the fuel tank (PLASTIC TANK). Use this for the capacitor value in the POT PBP command.
Maybe not so simple eh? :)
I wonder if a small current could be run up a couple of bare wires and use the fluid for a variable resistor.....without blowing up the tank that is.....which would be bad....but cool....once....

[JD123]

Thanks thanks thanks

I have to read a lot about it and test it...

JD123, what is it the <<window-alarm tape>>???

Nikos

At Radio Shack they use to carry Window Alarm Tape for DIY home alarm installations. The tape would connect to sensors and get cut if the glass was broken. Just the fact that I 'know' what this is, is dating myself. Radio Shack may not have this anymore. There are lots of places that carry self-adhesive foil tape (copper or tinned is best since you can solder to it). If you can't find this tape, you can use thin metal strips of whatever. Just be sure that it's in full contact with the tank for best results. That's why tape works best.

[JD123]

Maybe not so simple eh? :)
I wonder if a small current could be run up a couple of bare wires and use the fluid for a variable resistor.....without blowing up the tank that is.....which would be bad....but cool....once....

My guess it a 10KV pulse should be enough to do the job.

[skimask]

My guess it a 10KV pulse should be enough to do the job.
Well, at least then you'd know how much fuel was left in the tank....

None....

'cause there wouldn't be any tank left...

or a car....

[ngeronikolos]

http://www.tapes-direct.co.uk/index.php?main_page=product_info&products_id=933

Is that I am looking for???

[JD123]

I'm thinking more like the copper type so it can be soldered to:

http://www.can-dotape.com/foil-tape.htm#copper_foil

Here's a place on that side of the pond that has it. Slugs??? At least it's copper tape!
http://www.pestfree.co.uk/slugtape.htm

[Archangel]

Copper adhesive backed foil tape is available from any supplier of art glass, Tiffany glass, leaded glass supplier.

[JD123]

Copper adhesive backed foil tape is available from any supplier of art glass, Tiffany glass, leaded glass supplier.I should have known that - my Dad is into this big time.

[Acetronics2]

Hi, Gary

You're really Lovely ... like that !!! LOL

Hi, N'geron

I found something interesting in my old datas ...

No pic used, but working and nice to the "how" understanding ...

Alain