Building a Better Fuel Level Indicator.....

[lazy-b]

Guys, any idea of building a Better Fuel Level Indicator......

Have tried Building a 2 Probe.....have to drill a hole in the Fuel Tank....when the fuel is touch the 2 Probe fuel is OK.

Have also tried a Fuel Level and Battery Level Indicator made by HIROBO, Hirobo use a Capacitance sensor, one wire is submerge in the Fuel, and another wire is attach to the side of the Fuel Tanks with a Copper sheets stick on the side walling of the Fuel Tanks, there is a small trimmer at the control box that control the setting fuel level to make the LED on.

Can you suggest a Better Fuel level indicator......

been thinking of using a 2 thin sheets of Copper, stick on the 2 opposite side of a small Thin Fuel Tanks (Auxiliary Fuel Tank of Helicopter), the Capacitance of the 2 Copper foil is Higher when the Fuel tank is Full.

or can use some form of Optical sensor.....

Plan to use this for our Scale Helicopter.

Do you have a Better Idea.

[vintage1]

Capacitance is a really good system actually since fuel makes a decent dielectric.

Consider a probe of something like brass tube, split down the middle, and dipped in say epocy to insulate it (fuel is IIRC a little bit conductive as well).

Connect that via some thin coaxial cable (to get rid of stray capacitance variations) to a oscillator, and measure frequency..

[Tomapowa]

What ever you do, do not use the probe method when using gasoline as fuel (glow is typically OK). :eek:

I've messed with this idea a while back and never got something to work effectively and accurately... but in any case, here's a few ideas/links...

http://www.allelectronics.com/mas_assets//spec/L4620.pdf

http://www.discovercircuits.com/PDF-FILES/capgage.pdf

http://www.datasheet4u.com/html/Q/T/3/QT301_QUANTUM.pdf.html

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=GEMFG

[Acetronics]

Hi,

A little link to something capacitive working in real life ???

http://membres.lycos.fr/ezrc/TEXTES/EZFILL/r%E9sum%E9%20EZFILL.htm

Click on " Fichiers" tab ...

Yess ... in French, but BabelFish is your friend.

Processors must be ordered from this site ( symbolic price ...)

Alain

[darkith]

I've always wondered if you could put a clear tube connected at the bottom and top of the tank, and float a small dark hollow ball in it. Then use the ball to interrupt optical sensors or something. Similar to the full/empty gauge on the side of a electric kettle.

Dunno how well it would work in a bouncing plane...but might work if you were able to average a number of readings to compensate for g-forces and bubbles.

Since I've gone electric, I never tried it.

D.

[jeffs555]

Don't know if it would work in a small tank, but ultrasonics are used in some full scale tanks to measure distance from top of tank to the fuel.

[Tomapowa]

I've always wondered if you could put a clear tube connected at the bottom and top of the tank, and float a small dark hollow ball in it. Then use the ball to interrupt optical sensors or something. Similar to the full/empty gauge on the side of a electric kettle.

That's funny... I built something similar years ago with pretty good success. I used a tube (inserted into tank) with a small neodynium magnet attached to a piece of foam that floated inside the tube (floats to level of fuel). I then had a magnetic reed switch attached to the outside of the tank (close proximity to tube/magnet) that got triggered when the floating magnet dropped below a certain level. This switch closure in turn lit a bright LED mounted to outside of plane and acted as a low-fuel warning indicator. Again... obviously not so accurate... but it worked!

I actually used a similar setup to auto-fuel a plane and it worked pretty good amazingly (sensed level at top of tank and auto-stopped my fuel pump).

[lazy-b]

Guys, Thanks for all your suggestion.....

Just found here a simple Liquid Optical sensor sold by RS-Component, cost about P 1650 ( USD 37), its used LED and Photo Transistor inside its encapsulated sensor.......the its only 3 wire, 2 wire for Power supply and 1 output is output, maybe can directly attach to Ultrabright LED. LED will just light up when Fuel Tanks is empty.

Here is the link to RS-component:
http://philippines.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294934505&Ntt=liquid+sensor&Nr=AND%28avl%3aph%2csearchDiscon_ph%3aN%29&Ntk=I18NAll&Ntx=mode%2bmatchallpartial&N=4294857793+4294833064&Nty=1&binCount=143#breadCrumb

Here its PDF files:

I like the Idea of putting a small Magnet on a Float, and using a different Magnetic Reed switch to sense its level.

[shanghai_fool]

I'm not sure if this wouold work with a muffler pressurized tank but I just did a quick experiment with a 4" glass of water and a Freescale MPXV5004G pressure sensor on a tube and it measured .900 volts empty and 1.350 volts full. That should be enough range to drive an indicator.

I will do some more experiments and let you know. Has anyone else experimented with a pressure sensor?

[lazy-b]

Guys, here is another Liquid Sensor from RS-Component.....its a small Modules that operate on 5 Volts......using also a 2 Metallic Probe.

Price is about P 1,635 ( USD 37)

this liquid sensor sense liquid by detecting free ions, unlike the commercial fuel level indicator that uses LIQUID Conductivity to sense the presence of fuel.

here its link:
http://philippines.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4390082

its very easy to installed on Fuel Tanks, just need to drill 2 small hole, smaller than the diameter Fuel Silicon Tubing, Insert the Silicon Tube then insert 2 pcs Brass Rod as the Metallic Probe.

here its PDF Files.

Inside the circuit could be the same circuits L4620 posted by TOMAPOWA........I remember, National Semiconductor use to have a chips that can detect Liquid Level using AC signal to avoid plating effect of metal probe.

here is the old chip LM1830
http://www.hobby-hour.com/electronics/fluid_level_control_schematics.php

[lazy-b]

Guys, Found a more simple Liquid Level Detector using a very common ICs.....it uses AC signal to avoid plating of Sensing Probe:

http://www.uoguelph.ca/~antoon/circ/sensor3.htm

[lazy-b]

Guys, any idea of making a Float that can lift a small magnet ?

my idea is to make a float with a small magnet in it......then I can install a Reed Switch or a Hall-effect sensor to detect the Position of the Float.....look like this is a better fuel level indicator, cause no need to drill a hole on the Fuel Tank.

Will install the Magnetic Float in a Auxiliary tank, its a small Rectangular shape fuel tank. this will make the Float stay in a smaller area, and its easier to install a Reed switch or Hall-effect sensor.

look like I can use a bigger silicon tubing with a thinner wall.

[lazy-b]

Guys, have able to make the small Magnet Float by using a Silicon Fuel Tubing with an outside diameter of 5.5 mm and a inside diameter of 3.5 mm and about 2 inch long.....I put it inside a Transparent plastic container with Water in it.

I installed a small Magnetic Reed Switch outside the container, but the Magnet is not strong enough to activate the reed switch.

Next time will try to experiment using a Hall-effect magnetic sensor..........