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0-5v output to 233-40 ohms linear circuit for fuel press. gauge

Discussion in 'Automotive Electronics' started by Savannarail, Oct 29, 2017.

  1. Mosaic

    Mosaic Well-Known Member

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    Well it seems like a 25 % step can be represented by a y=mx+c best fit line which can be setup to cover your desired range for the req'd accuracy.
    This can then be verified and calibrated by yourself using trim pots and your good PSI gauge/air pressure.

    That should be doable without a microcontroller by using a decent opamp or 2 and a low output impedance as the gauge ref. voltage to convert/display the PSI value.

    So, yes, I think it can be done economically and effectively within those parameters.
     
  2. Mosaic

    Mosaic Well-Known Member

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    BTW...slightly OT,but here are some pics for a round and rectangular version of the same gauge/controller , a marketing blurb and a user manual that , well, is daunting in the amount of features (18 menu trees) including electronic BOV control for optimum boost retention during gear shifting and reuse.
    Damn thing took me over a year to do.
     

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  3. Savannarail

    Savannarail New Member

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    Wow - Very impressive ! I bet it did take a while. You should get set up to make high volumes and start selling these along with the components as a package. Megasquirt users, for starters, would probably jump all over them !!

    On the Converter, is there a schematic already out there I can use or.. ?

    Also, will the converter "Feed" the gauge with a voltage or resistance ? I do not understand that part. Since the Stock FP Sender has a 5v reference to the sensor then outputs a voltage based on pressure, I do not think the gauge can use that voltage directly so the need for the "converter". The gauge wants a resistance to work correctly, is that right? I'm not getting how the converter works with the gauge.

    BTW - Hows the Tesla Solar charger project going ? I just put solar on my house and am gradually reducing my "on-Peak" usage thru different means while making them transparent to our daily routine (especially for the wifey). Using solar for different projects has always interested me.
     
  4. dave

    Dave New Member

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  5. Mosaic

    Mosaic Well-Known Member

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    The converter will convert the 0-5V signal to a voltage signal which replaces the voltage developed by the gauge across the resistance based sender.
    No i haven't done the schematic yet....kinda working on a couple things including a power conditioner for the FT 817 transceiver and I have to 'shark tank' type pitch for a $5K USD grant investment next week for another project.
     
  6. Mosaic

    Mosaic Well-Known Member

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    I'll just open source it with a Hackaday project for others to make or do more dev. No time to make another product now and automobile products (Electronic Sub Assy) need too many certifications for me to invest in this so it's gonna be DIY.
     
  7. Savannarail

    Savannarail New Member

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    Just an idea, many companies sell ECU's and accessories both ready to go and in KIT form. Maybe present to them to produce and sell and you get a percentage of each sale. I'm just saying I think your creations are more than good enough to be marketable. Also the ECU's are only to be used off road.
     
  8. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    A reminder: Most automotive sensors use a relative rather than absolute reference. e.g. It's relative to the 5V supply. It;s also why 100% is not 5V. Industrial sensors have a 0-5V output, and 5V is usually full scale. If the 5V supply happens to be 4.9V when the measurement is taken relative to that value.

    It's actually a good thing.

    Usually 0V is unobtainable, so a 0V out from a sensor won't happen either.
     

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