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Old 22nd April 2008, 02:37 PM
les g les g is offline
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Join Date: Jan 2008
Location: S.E.Cornwall
Posts: 760
Default fuel gauge idea

what about the other type of float switch on the Maplins website
perhaps three arranged vertically
to three leds /lamps
red/amber /green
low /half full /full
what do think good /bad/crap/or bloody stupid ???????
any thoughts
les g:
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Old 22nd April 2008, 03:45 PM
jabs jabs is offline
Join Date: Apr 2007
Location: Knaresborough, Harrogate
Posts: 59

A little coarse, the last one could be set so you have say 1 gal left in the tank when it comes on. Also there would be no damping so as you go around corners it would be disco lights
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Old 22nd April 2008, 05:19 PM
les g les g is offline
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Join Date: Jan 2008
Location: S.E.Cornwall
Posts: 760

ok yep i can see that
what about some baffling in the tank
or could they be wired in someway that they only trip the light if the float is continually activated for a specific time ie some kind of smoothing
or could thy to say five lights so at some position two floats are operating intermediate lights
any thoughts any clever electrical boffins??????
or just forget as too!!!! much hassleand junk the idea""""""""
les g
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Old 30th April 2008, 08:17 AM
snapper snapper is offline
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Join Date: May 2007
Location: Chelmsford, Essex
Posts: 360

The output from the sender follows a specific range of resistance and with a little clever electronics is all you need to trigger the LED's.
Standard senders run 33 Ohms full tank to 240 empty.
You could have all LED's on when full and loose one every time the fuel level drops past a certain point.
With 5 LED's you could have 3 green 1 yellow and one red.

United States Patent 4102191 Link to this page:http://www.freepatentsonline.com/4102191.html Abstract:A digital readout fuel gauge for monitoring the liquid level in a fuel storage tank. The device utilizes a pre-amplifier circuit which comprises a voltage divider network utilizing the fuel gauge tank variable resistor on one side of the divider and a variable resistance on the other side which is connected to a signal processor. The output voltage of the signal processor is connected to the analog input of an analog to digital converter. The analog to digital converter changes the DC voltage levels to a four bit BCD code. The output carrying the code is connected to a decimal digit to a seven segment LED decoder. The digits are generated and displayed on LED indicator units. In addition, a voltage comparator circuit compares the output of the signal processor with a reference voltage and when said output is below a predetermined level, the comparator circuit initiates a warning signal.
Down to Maplin it is then
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Old 30th April 2008, 04:17 PM
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Josh Josh is offline
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Join Date: May 2007
Location: Bromley
Posts: 160

It wouldn't be to hard to do a DIY circuit that waits for say 4-5 secs before accepting that the fuel level really is that low, not just cornering. Would almost cirtainly need the use of a PIC (proggramable intergrated chip) and a little know how though. Try searching for 'PICAXE', I've used many of these chips and they have a great 'teach your self' section.

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Old 30th April 2008, 06:22 PM
Chris Gibbs
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That's the sound of anything electronic going over my head!


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