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 [DPRG] Sensor ideas Message index sorted by: [ date ] [ thread ] [ subject ] [ author ] Previous message: [DPRG] Sensor ideas Next message: [DPRG] Meeting This Saturday -- Annual Election -- We need your help! Subject: [DPRG] Sensor ideas From: A. Scientist angryscientist at gmail.com Date: Thu Jan 7 08:35:53 CST 2010 ```How about an acewell fuel sending unit? Looks like they might be a bit pricey though as they arent a US company. I see a few on ebay for ~\$70AUD. On Wed, Jan 6, 2010 at 5:38 PM, Sluggy! wrote: > Greetings, All! > > Long time, so seize. I have been a-lurking, though.... > > Whilst lurking, I am doing another EFI conversion, this time on an air > cooled VW engine. http://msruns.com/viewtopic.php?f=88&t=22894 > > One of the problems I need to solve is operating the fuel gauge. > > The instrument I have http://tinyurl.com/ykje3lc wants to read a > resistance between 0 and 100 ohms corresponding to the level of fuel in the > tank. Since the tank is basically a hand fabricated 1 foot cube, there is > not really a factory tank sensor that is actually made for it, at least not > a cheap one. I am investigating salvage sensors, but it would be nice if I > could use the one that is already on my fuel pump. > > The fuel pump I'm using is an in-tank unit that was salvaged from a > Kawasaki motorcycle, a model that is equipped with a fuel gauge. The stock > sensor, however, is basically a variable capacitance sensor. At this > writing, I don't know what the range is, other than either empty or full is > approximately double the capacitance of the other state. I need to convert > that capacitance into a variable resistance. There is a chance that a > variable voltage may work; I will have to investigate that separately. > > I'm contemplating a circuit that converts capacitance into either a > pulsewidth or a frequency, then use that value to adjust a digital > potentiometer like these http://www.maxim-ic.com/products/digi_pot/ > > Unfortunately, it appears that 10Kohm is the smallest end-to-end value and > 64 steps is the smallest increment, so the smallest change I can affect is > 156 ohms. That doesn't even consider that there is a minimum series "wiper" > resistance of 100ohms. > > By paralleling the digi-pot with a fixed resistor, I can get a piece of the > range. 10K + 100 = 99.01 ohms, which is good. but minimum is 256 + 100 = > 71.91, giving me a workable range of roughly the 1/4 tank. > > Anyway, does anyone have any ideas or suggestions for this problem? > > Thanks! > > Robert/Sluggy! > > > _______________________________________________ > DPRGlist mailing list > DPRGlist at dprg.org > http://list.dprg.org/mailman/listinfo/dprglist > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://list.dprg.org/pipermail/dprglist/attachments/20100107/e2c1e961/attachment.html ``` Previous message: [DPRG] Sensor ideas Next message: [DPRG] Meeting This Saturday -- Annual Election -- We need your help! Message index sorted by: [ date ] [ thread ] [ subject ] [ author ] More information about the DPRG mailing list