Hi All,

I finally got round to testing out my fuel guage set up last night which I have cobbled together from random components. And shock horror it doesn't work properly. I have a sender of unknown origins and a smiths guage. The sender operates from 50 ohms (empty) to 285 ohms (full). Unfortunately when connected to the smiths guage it works in reverse! Full shows empty and empty shows 3/4 full!

So my question is does anyone know if there is something clever I can do to reverse the signal or alternatively know of a cheap guage that works over that range?

Cheers

Chris

You can reverse the logic of ana analogue signal with some simple circuitry...

see here

http://www.maxim-ic.com/appnotes.cfm/an_pk/1129

Float type sensor?
Turn assenbly upside down so when full the float is where it was when empty.
Darren

The sensor is the 'float on the end of an arm' type. So I am stuck with it in it current position I am afraid.

Chris

quote:

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Originally posted by chris-p-duck
The sensor is the 'float on the end of an arm' type. So I am stuck with it in it current position I am afraid.

Chris

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This happens on mine and what I do is when I see the arm heading towards 3/4 full I put more petrol in.
But seriously, no I just put up with it. It'll be a Winter fix I think.

Is it one of this type? (Smiths/Greenguages)



If so, you could try sliding the resistor box off the end, turning it over 180 degrees, and refitting it to the shaft. You'll probably have to bend the wire a bit to make it work again.

or, could you just swap the wires around on the gauge?

My sender is similar to that diagram except that the pivot is fixed to the upper mounting plate and not on a drop down arm.

Swapping the connectors round was my first though! Didn't make any difference unfortunately!

Chris

Why not mount the fuel sender from underneath the tank, then it will read the other way round.

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Originally posted by dunk3
Why not mount the fuel sender from underneath the tank, then it will read the other way round.

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why not buy matching sender and gauge job done

quote:

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Originally posted by x_flow57

quote:

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Originally posted by chris-p-duck
The sensor is the 'float on the end of an arm' type. So I am stuck with it in it current position I am afraid.

Chris

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Not necessaraly, I bent my "arm" through 180deg, adjusted the angles so it was accurate on empty and turned the sender upside down.

Nick

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solved my issues by using sender from a mini petrol tank i had lying about.

the senders are actually made by smiths so generally compatable

i also used a smiths fuel gauge.

i found i had to bend the arm to hit the Empty stop early to stop it reading past "E" as the travel on the mini tank is much greater and narrower at bottom, therefore resistor winding is a bit more Spaced out at the last 1/4.?

also - clean up the arm pivot as it carrys earth back to body of sender.

that last last sentence sounds like a crossword clue!