Jump to content

Fuel meter


kbelcar
 Share

Recommended Posts

  • 2 weeks later...

Just to re-awaken the debate, I've just bought a capacitance meter off ebay that I'm going to try hooking to a home-made capacitive probe (with designed in anti-slosh factors). As the meter is PIC based, then hope to rework the code to read 0-100% with a reset button to hit when full. Would be configurable in the firmware for odd shaped tanks. The meter board can run off 9v, so no independent supply required, although usable if you have one.

I know all about KISS, but hey, with non-flying time on my hands, you can only polish a prop so many times!

Link to comment
Share on other sites

Hi Alan, never used one before, and the closest I have come to writing in 'C' was probably back when I did my 'O' level computer studies (remember those) about 33 years ago when we programmed in 'Mini'. Probably some of the first in the UK to do so. Back then we coded onto optical mark cards with pencil, and sent them away to be run. One pencil mark in the wrong place and the programme would hang. A week later, our run results were posted back to us. Writing in 'BASIC' was slightly easier as we used a Teletype to write to punch tape, and when we'd written it, we used an acoustic coupler on the phone to connect to the treasury computer in Newcastle on Tyne (I think) and we got the output back on the TTY.

By the time I left school, ISTR we actually had a 'PET' on site, and the brother of my G/F who used a PDP9 was hard-core!

Tell that to the kids of today..........

Oh, and I may well pick your brains!

Phil

As the meter is PIC based,

Hi Phil, are you a fan of PICs as well, I've done a few projects with them.

If you need any help give us a shout.

Cheers,

Alan

Link to comment
Share on other sites

Phil

I have the Maplin PIC programmer/emulator board that Im not using if any use. I used it once to do a small programme for a servo. I also bought a tutorial book on programming etc that I started to read but kept falling asleep by page 5, so got the programme I wanted of the tinternet and loaded it on the pic via the board, it was easier and saved me from reading the book Lol

Cheers

Gary

Link to comment
Share on other sites

Hmmm, now that looks interesting, wonder what power source would be needed? There is also a bendable version which would be useful?

Has anyone used this yet?

Bignos.............are you going to be the first one trying to use this? I am not that adventurous (or skilled enough)in drilling holes in my tank to find it doesnt work?

Fuel gauges have been a big topic of debate until someone comes up with something new?

I do use a mirror, but sometimes in bright light it becomes difficult to assess especially when you're really down low on fuel?

When someone comes up with a full proof method of accurately reading fuel in the tank everybody will start modifying their tank.

Mike

Link to comment
Share on other sites

A few years ago many of us were using a device called a Quest XC. It had many useful feature such as a calibrated fuel sensor which told you exactly how much fuel was in your tank regardless of the tank shape. It's navigation displays would also give you a real time wind vector which along with other parameters would give you an accurate fuel on arrival or fuel on return to home figure.

Link to comment
Share on other sites

I'm going to try hooking to a home-made capacitive probe (with designed in anti-slosh factors).!

What form does your probe take :?: (Cor that's a leading question isn't it :? )

I have looked at the circuitry for the analogue sensors similar to http://shop.airworlduk.com/airworld-sol ... -142-p.asp and it is quite simple.

If you have an easy to make sensor design I might try to knock one up.

Cheers,

Alan

Link to comment
Share on other sites

Brass tube, approx. 10mm diameter, with brass rod, approx. 1.5mm diameter running down centre. Isolated from each other with delrin spacers top and bottom. two small holes drilled in outer tube close to top and bottom spacer disks, enough to admit petrol, but small enough to damp fluctuations. If the capacitance of the above is too small, will shift to smaller tube.

Bailey tank has a spare 'bung' in the top, the sensor should hook up to a BNC socket that goes through the bung, that'll give a suitable termination for the cable to the meter.

Would prefer to use aluminium, but ease of soldering brass makes it attractive. Even riveted terminations onto aluminium tend to degrade over time with oxide accumulation.

Have a double sided BNC socket to mount through bung, so sensor can be built onto a BNC plug for ease of changing.

Is 'hot glue' HDPP? if it is, it'd make good sealant.

Link to comment
Share on other sites

Have a double sided BNC socket to mount through bung, .

Excellent idea that Phil, particularly as I have one of those.

I think you need to re-evaluate the sizes of your probe. The capacitance is going to be very small with the internal gap you are proposing. One of the articles I read suggested a gap of 1.5mm between the inner and outer elements of the sensor. A circuit I have is showing 100 to 170pF for the range of the sensor from empty to full.

Searching through the 'junk' store I came across this 'constant-impedance adjustable line'

573363f127ce4_MeontheFusion.jpg.cebe2b6e

Detail.JPG.904e953438c5c01acdcf09d19353a

Link to comment
Share on other sites

You may be right about the low values with my proposed set up.

Currently on the bench dry, I am getting about 14pF. I may try immersion in fuel tomorrow.

How about inserting an extra 'layer' between my present inner and outer conductors, perhaps something like some 8mm tube? It could then be configured so that inner and outer are common ground, and the intermediate tube connect as +ve That would presumably double up on capacitance, and also improve the gradient of the response, as every extra bit of fluid would create a larger incremental increase.

Another little project on my mind is a small version of the radar reflectors you see on boats (sort of diamond shape made up of flat plate). To improve radar visibility passively. Suspect there may be a critical size however, based on radar wavelength. I think Waddington LARS would help confirm or otherwise, the functionality.

Oh boy, too much time on hands. Hopefully trike welding is happening next weekend.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share



  • Upcoming Events

    No upcoming events found
×
×
  • Create New...