THe NAC Lots-O-BFG KO2 Thread

[asp]

Re: THe NAC Lots-O-Post Thread

Ken, you mentioned in that thread about the non-linearity of the fuel gauge response, even in an OEM application. I've been half-baking ideas to try and fix that on my Dodge for over 3 years...

http://www.pirate4x4.com/forum/showthread.php?t=638897&highlight=linear+fuel+gauge

I think my original idea had to do with recording the resistance at each gallon mark to build a calibration curve for the stock sender, then use that to get a straight % of fuel remaining from the sender reading, and convert it to the appropriate resistance for whatever gauge I was using. Basically obtaining both calibration curves by experimentation and creating one function to go between the two.

Just what I need, more project resurrections...

I've noticed that issue in almost every car I've ever owned or driven but didn't know where the problem generated from. I just knew it stayed 'full' longer than it should then promptly plummetted towards E. I don't know what VW did, but my GTI seems to not have this issue. My gas gauge has already gone down a touch when I've only gone about 30 miles (at 30mpg) after a fill when it took 50-75miles (at 18mpg) to register the same change in the gauge as my XJ.

 

[XJLI]

Re: THe NAC Lots-O-Post Thread

my 98 does it more so than my 93 did, and my subie was terrible at that. first half tank lasted forever, then the second half was gone instantly.

 

[kastein]

Re: THe NAC Lots-O-Post Thread

Ken, you mentioned in that thread about the non-linearity of the fuel gauge response, even in an OEM application. I've been half-baking ideas to try and fix that on my Dodge for over 3 years...

http://www.pirate4x4.com/forum/showthread.php?t=638897&highlight=linear+fuel+gauge

I think my original idea had to do with recording the resistance at each gallon mark to build a calibration curve for the stock sender, then use that to get a straight % of fuel remaining from the sender reading, and convert it to the appropriate resistance for whatever gauge I was using. Basically obtaining both calibration curves by experimentation and creating one function to go between the two.

Just what I need, more project resurrections...

Exactly what I was going to do, but going down to half or quarter gallons just for the hell of it. The ADC I'll probably end up using will be an 8 bit one, which will give 256 different readings total of course, so technically I could go down to approximately 12ths of a gallon with decent accuracy, at which point corners/hills will change the reading more than a tick so who cares.

Instead of actually creating a function I was going to simply have a 256 entry lookup table to convert between the ADC reading and the value to send to the digipot. So the code would really just be setup (probably enable a timer interrupt, initialize a few pointers, then set up an ISR and go to low power mode) and an ISR that would grab the value from the ADC, look up the value in the table, write it to the digipot via i2c/spi and then go back to sleep.

 

[rweaver138]

Re: THe NAC Lots-O-Post Thread

i try not to pay too much attention to my gas gauge.. it makes me feel a bit better when i just put the gas in and don't know how much im wasting lol

 

[asp]

Re: THe NAC Lots-O-Post Thread

http://vimeo.com/18557380

Wow, wicked cool.

 

[vetteboy]

Re: THe NAC Lots-O-Post Thread

Yep, a discrete table would certainly work too...I was just gonna plot the bare minimum of data points possible to get a smooth curve, have a function that evaluated the input, then rounded & converted the output back to binary. Ya know, save me the trouble of making a 256-entry table. :laugh:

I don't know how factory gauges are buffered, but it'd be easy enough to create an artificial buffer in this case by messing with the write interval for the digipot and setting a maximum delta for each interval.

 

[foxwar71]

Re: THe NAC Lots-O-Post Thread

Ross, I might show up if you're around so I can buy those bumpstops, pick up the springs, and shit I completely forgot the other thing again.

How am I supposed to remember?!?! You also wanted to swap t-cases, maybe that was it? :dunno:

Just txt me ahead of time, I may out comsuming beers.

 

[rweaver138]

Re: THe NAC Lots-O-Post Thread

mom mad some chili for the superbowl, eating some leftovers right now with melted shredded cheese on top.. its delicious

 

[kastein]

Re: THe NAC Lots-O-Post Thread

How am I supposed to remember?!?! You also wanted to swap t-cases, maybe that was it? :dunno:

Just txt me ahead of time, I may out comsuming beers.

yup you're right on that one. Sadly it's sitting on my kitchen counter at the house, so that one will have to wait I guess.

 

[5spd_xj]

Re: THe NAC Lots-O-Post Thread

hummm dee dummmmm. I wanna work on my Jeep dee dum dummmmm.

 

[asp]

Re: THe NAC Lots-O-Post Thread

I don't mean to put my foot in my mouth here, but I'm planning on doing that tonight.

 

[vetteboy]

Re: THe NAC Lots-O-Post Thread

Satan just called, he said the heat must be broken, 'cuz it's getting kinda cold down there.

 

[RCman]

Re: THe NAC Lots-O-Post Thread

Who is actually going?

arty:

 

[kastein]

Re: THe NAC Lots-O-Post Thread

Oh and Ross... I would alert you ahead of time but I can't. I completely demolished the screen on my phone about a week ago. The only thing that works is receiving calls, and I have no idea who is calling till they start talking.

 

[foxwar71]

Re: THe NAC Lots-O-Post Thread

Haha, I like the ninja edit. This one brings the funny.

 

[foxwar71]

Re: THe NAC Lots-O-Post Thread

Oh and Ross... I would alert you ahead of time but I can't. I completely demolished the screen on my phone about a week ago. The only thing that works is receiving calls, and I have no idea who is calling till they start talking.

If Im not around or napping or dont feel like coming outside, I'll leave them sitting on the hood of black jeep.

 

[cmelo]

Re: THe NAC Lots-O-Post Thread

:dunno: whatever, there's not much snow on it. Its pretty easy to unbury, I also have the pathway clear. Black jeep is even kinda shoveled out and unburied!!

I'll be around the rest of the day if you want to do it.

 

[cmelo]

Re: THe NAC Lots-O-Post Thread

he's close....10-2 but I often stay later. will shoot you a reply pm in a little bit.


anyone free in the area tonight, Dunderson & I will be heading to the 99.

Time?

 

[cmelo]

Re: THe NAC Lots-O-Post Thread

Colin I've got your shit in my Comanche if you want to call me later to get it.

 

[asp]

Re: THe NAC Lots-O-Post Thread

Satan just called, he said the heat must be broken, 'cuz it's getting kinda cold down there.

Nope, there's a half tank of diesel and the system is primed :laugh3: