[DeTomaso] Fuel Gage Linearizer

John Taphorn jtaphorn at kingwoodcable.com
Sun Nov 2 10:11:57 EST 2008 

Dang it, Ed

I just watched your video on YouTube.  I appreciate your commitment to 
optimizing bizarre devices.  You are unique!

Very cool

JT
----- Original Message ----- 
From: "Edward A. Nauman" <enauman at roadrunner.com>
To: "'John Taphorn'" <jtaphorn at kingwoodcable.com>; "'Email Forum Pantera'" 
<detomaso at realbig.com>
Sent: Sunday, November 02, 2008 8:05 AM
Subject: RE: [DeTomaso] Fuel Gage Linearizer


> Thanks for the info.  I don't want to give the impression that I'm trying 
> to
> market the device.  I just wanted to make it available to the guys if they
> were interested.  Regarding Thomas' device, it sounds like the same
> principal only the EEPROM is built into the microcontroller in my case. 
> The
> box I built will work with any combination of sender/gage in the 
> automotive
> industry.  It wouldn't take very much additional programming to make user
> calibration possible.  It has an RS232 port built in and the PIC is an "in
> circuit" programmable device.  Like everything I design for myself, it's
> over engineered so it would be expensive to market it with the intent of
> making money.  Besides I like production manufacturing about as much as I
> like root canals...  :)  Here is a link to another design that I did for 
> fun
> that would never make it to the merchandise shelves.
>
> http://www.youtube.com/watch?v=xtlN_9sXn3c
>
> Cheers
>
> Fast Eddie
>
> Edward A. Nauman\
> C.E.O.
> Smart Litez Inc
>
> Palmdale, CA. 93551
> (661) 305-7636
>
>
>
>> -----Original Message-----
>> From: John Taphorn [mailto:jtaphorn at kingwoodcable.com]
>> Sent: Sunday, November 02, 2008 5:43 AM
>> To: Edward A. Nauman; Email Forum Pantera
>> Subject: Re: [DeTomaso] Fuel Gage Linearizer
>>
>> Ed
>>
>> Several years back, Thomas Tornblom offered his electrical engineering
>> expertise to the group with an alternative solution he called his Gauge
>> Corrector.
>>
>> It is an adjustable eeprom to match the sender to any gauge.  If I
>> recall
>> correctly, the eeprom can store 10 data points.  Thus, I was able to
>> adjust
>> my fuel gauge to read accurately at 1/8th intervals by filling the tank
>> 2.65
>> gals at a time and storing the value.  Of course, it assumes that the
>> quantity of fuel used between those data points is linear for a given
>> drop
>> in the float arm.  However, accuracy at 1/8th intervals is close enough
>> for
>> me.  Obviously, if you are using a data point for every gallon verses
>> 2.65
>> gals, your approach will be more accurate between my 1/8th data points.
>>
>> Although a benefit of Tom's eeprom approach is that I was able to
>> calibrate
>> it myself and could easily perform the operation again should I change
>> my
>> gauges to a set with a different impedance.  I.E. I am currently using
>> it on
>> my Auto Meter, but could have used it on my Veglia initially.
>>
>> I don't know if Thomas is still offering the product.  It was very
>> inexpensive and has the JT Seal of Approval.
>>
>> I am not trying to discourage your idea or willingness to help, simply
>> illuminating the possibilities and the contributions of others.
>>
>> JT
>>
>>
>> ----- Original Message -----
>> From: "Edward A. Nauman" <enauman at roadrunner.com>
>> To: "Email Forum Pantera" <detomaso at realbig.com>
>> Sent: Saturday, November 01, 2008 1:56 PM
>> Subject: [DeTomaso] Fuel Gage Linearizer
>>
>>
>> > Hi guys,
>> >
>> >        I have been away from the list for a while and was searching
>> > through
>> > the archives.  I came across a message about a circuit I designed a
>> couple
>> > of years ago.  Being an instrumentation engineer for 3 decades, one
>> of my
>> > pet peeves developed over the years is the non-linearity of
>> automotive
>> > fuel
>> > gages.  The fuel gage in most cars is really a fuel level gage and
>> not a
>> > fuel quantity gage.  Since the fuel level transducer is usually a
>> > wire-wound
>> > potentiometer actuated by a float at the end of an arm, the
>> potentiometer
>> > output is proportional to the angle of the float arm which is a
>> sinusoidal
>> > function.  Most of the automotive fuel level pots I have examined
>> have a
>> > linear output with respect to rotation angle of the shaft.  So, the
>> fuel
>> > level with respect to the output of the potentiometer becomes a
>> function
>> > of
>> > the length of the float arm and the sin of it's angle.  In other
>> words the
>> > measurement, if uncorrected, is non-linear.  This is sometimes
>> corrected
>> > for
>> > by manufacturing a non-linear pot that linearizes the sinusoidal
>> output in
>> > the range of interest.  Remember, that is for fuel LEVEL.  When you
>> > translate level into quantity. The shape of the fuel tank becomes the
>> next
>> > source of non-linearity.  Obviously if you had a cone shaped tank,
>> one
>> > inch
>> > of fuel level near the top is a lot more than quantity 1 inch at the
>> > bottom.
>> > Depending on the irregularity of the cross-sectional area of the tank
>> as
>> > the
>> > fuel level rises, the equation for quantity Vs. level can get quite
>> > complicated.  The simplest way to correct the situation and still be
>> > adaptable to different tank shapes and sizes is to use a micro-
>> controller
>> > and a calibrated look up table to translate the level into actual
>> > quantity.
>> > The design I came up with for my car uses a PIC microcontroller that
>> has
>> > on
>> > board an EEPROM to store the look-up table.  Operationally, the fuel
>> level
>> > potentiometer is connected to my circuit which reads the resistance
>> and
>> > "looks up" the correct corresponding fuel quantity. It then drives
>> the
>> > gage
>> > with the correct voltage to indicate the actual quantity.  The setup
>> > requires calibrating the tank at 1 gallon intervals which means
>> draining
>> > the
>> > tank and filling it one gallon at a time.  Since I was only building
>> one
>> > of
>> > these circuits for myself, I did not write any code to have the micro
>> > perform the calibration automatically, meaning, that I recorded ADC
>> output
>> > on my computer, generated the lookup table with Excel and manually
>> entered
>> > the lookup table into the micro.  I did the same thing for the one I
>> built
>> > for Chuck Buthala.  But that meant he had to perform the calibration,
>> > email
>> > me the data, and I programmed his look up table and sent the box to
>> him.
>> >
>> >        If you guys are interested in something like this, I can do 1
>> of 2
>> > things.  I can put together a kit consisting of a PCB and a parts
>> list
>> > with
>> > a schematic and a wiring diagram.  Or, I can build you one and send
>> it to
>> > you with installation instructions.  But unless you are familiar with
>> PIC
>> > microcontrollers and own a programmer, you would have to send me the
>> data
>> > and I would have to program it and send it back to you.  In order for
>> me
>> > to
>> > write the code for an auto calibration routine, I would have to have
>> > enough
>> > commitments to justify the time spent.  Bear in mind, I'm not trying
>> to
>> > make
>> > money here, just offering this to my Pantera brothers if they are
>> > interested.  If there is enough interest, I will figure out a price
>> based
>> > on
>> > the responses I get.
>> >
>> >
>> >        Cheers,
>> >
>> >               Fast Eddie  (#2100)
>> >
>> >
>> > P.S.  If my explanation is either too complicated or too simple,
>> please
>> > let
>> > me know and I will clarify any questions you may have.
>> >
>> >
>> >
>> >
>> >
>> > Edward A. Nauman\
>> >
>> > C.E.O.
>> >
>> > Smart Litez Inc
>> >
>> >
>> >
>> > Palmdale, CA. 93551
>> >
>> > (661) 305-7636
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >>The circuit was designed by Ed Nauman.  He built one for me and it
>> works
>> > great.  The gizmo works with a chip which uses the sending unit
>> > resistance,
>> > compares it to a look up table in the memory and >sends the correct
>> signal
>> > to the gage.  You have to go though a calibration cycle to set it up.
>> > There
>> > is an article in the POCA news about two years ago on the circuit.
>> Ed if
>> > your listening I hope my >description is correct.
>> >
>> >>"www.ProvaMo.com" <pantera007 at sbcglobal.net
>> > <http://list.realbig.com/mailman/listinfo/detomaso> > wrote:   It was
>> not
>> > "Me" Chuck that Ohm'ed, but I did test one gallon at a time, the
>> >>ohming was, I think, someone in the Nordic region perhaps.
>> >
>> >>Chuck
>> >
>> >
>> > -----Original Message-----
>> > From: detomaso-bounces at realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso>
>> > [mailto:detomaso-bounces at realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso> ]On
>> > Behalf Of Mark McWhinney
>> > Sent: Tuesday, July 24, 2007 10:41 AM
>> > To: 'Garth Rodericks'; detomaso at realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso>
>> > Subject: Re: [DeTomaso] Incorrect gas gauge
>> >
>> >
>> > Some of the fancier aftermarket gauges allow for multiple calibration
>> > points. I think little Larry has that. If he is lurking, may he can
>> fill
>> > us in.
>> >
>> > As I recall, Chuck did the one-gallon at a time work to record the
>> ohm
>> > readings.
>> >
>> >
>> > -----Original Message-----
>> > From: detomaso-bounces at realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso>
>> > [mailto:detomaso-bounces at realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso> ] On
>> > Behalf Of Garth Rodericks
>> > Sent: Tuesday, July 24, 2007 10:33 AM
>> > To: detomaso at realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso>
>> > Subject: [DeTomaso] Incorrect gas gauge
>> >
>> > Just another reference point for the non-calibrated nature of our gas
>> > gauges.
>> >
>> > When mine is full it registers Full.
>> > 40 miles after fill up it registers at the 3/4 mark, or slightly
>> below.
>> > But I can drive for quite a long time between 1/2 tank and Empty.
>> > And, at Empty the warning light comes on.
>> >
>> > I have not tested how far I can go after the warning light comes on,
>> > however the most I've
>> > been able to add at a fill up was 19.5 gallons.
>> >
>> > Now, I recall a year or two back that someone posted that they made a
>> > simple electronic
>> > converter to calibrate the fuel gauge. I think they took ohm readings
>> from
>> > the sender as they
>> > filled the tank 1 gallon at a time, then created a mapping table to
>> send
>> > an accurate reading
>> > to the gauge. Does anyone remember who that was? I recall they were
>> > planning to make it
>> > available for sale, but I never saw anything more on it. Does anyone
>> have
>> > more info? I'd like
>> > one.
>> >
>> > Cheers!
>> > Garth
>> > #4033
>> >
>> > YMMV,
>> > Garth
>> > #4033
>> >
>> >
>> > ---------------------------------
>> > Need a vacation? Get great deals to amazing places on Yahoo! Travel.
>> > _______________________________________________
>> >
>> > Detomaso Forum Managed by POCA
>> >
>> > Archive Search Engine Now Available at
>> http://www.realbig.com/detomaso/
>> >
>> > DeTomaso mailing list
>> > DeTomaso at list.realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso>
>> > http://list.realbig.com/mailman/listinfo/detomaso
>> >
>> >
>> > _______________________________________________
>> >
>> > Detomaso Forum Managed by POCA
>> >
>> > Archive Search Engine Now Available at
>> http://www.realbig.com/detomaso/
>> >
>> > DeTomaso mailing list
>> > DeTomaso at list.realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso>
>> > http://list.realbig.com/mailman/listinfo/detomaso
>> > No virus found in this incoming message.
>> > Checked by AVG Free Edition.
>> > Version: 7.5.476 / Virus Database: 269.10.17/915 - Release Date:
>> 7/24/2007
>> > 1:50 PM
>> >
>> > No virus found in this outgoing message.
>> > Checked by AVG Free Edition.
>> > Version: 7.5.476 / Virus Database: 269.10.17/915 - Release Date:
>> 7/24/2007
>> > 1:50 PM
>> >
>> > _______________________________________________
>> >
>> > Detomaso Forum Managed by POCA
>> >
>> > Archive Search Engine Now Available at
>> http://www.realbig.com/detomaso/
>> >
>> > DeTomaso mailing list
>> > DeTomaso at list.realbig.com
>> > <http://list.realbig.com/mailman/listinfo/detomaso>
>> > http://list.realbig.com/mailman/listinfo/detomaso
>> >
>> >
>> >
>> > ---------------------------------
>> > Pinpoint customers who are looking for what you sell.
>> >  _____
>> >
>> >
>> > * Previous message: [DeTomaso]
>> > <http://www.realbig.com/pipermail/detomaso/2007-July/086859.html>
>> > Incorrect
>> > gas gauge
>> > * Next message: [DeTomaso]
>> > <http://www.realbig.com/pipermail/detomaso/2007-July/086861.html>
>> > Incorrect
>> > gas gauge
>> > * Messages sorted by: [
>> > <http://www.realbig.com/pipermail/detomaso/2007-July/date.html#86863>
>> > date
>> > ] [
>> > <http://www.realbig.com/pipermail/detomaso/2007-
>> July/thread.html#86863>
>> > thread ] [
>> > <http://www.realbig.com/pipermail/detomaso/2007-
>> July/subject.html#86863>
>> > subject ] [
>> > <http://www.realbig.com/pipermail/detomaso/2007-
>> July/author.html#86863>
>> > author ]
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> > _______________________________________________
>> >
>> > Detomaso Forum Managed by POCA
>> >
>> > Archive Search Engine Now Available at
>> http://www.realbig.com/detomaso/
>> >
>> > DeTomaso mailing list
>> > DeTomaso at list.realbig.com
>> > http://list.realbig.com/mailman/listinfo/detomaso
>

More information about the DeTomaso mailing list