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★★★★Project Tracy★★★★ Wideband AFR - New product -ready to ship

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    ★★★★Project Tracy★★★★ Wideband AFR - New product -ready to ship

    So, many of you have seen my interior light delay with auto dimming that I make

    Hopefully this will spark some creativity from you all to go and explore on your own.

    So - ENOUGH of that BS, just what the hell is this? Well, my car is not turbo'ed. No Mega-squirt. I have no real need for super huge gauges all over my dash. I like the stock *look*. But I wanted to add an extra gauge here or there, and yet have the interior look totally stock. So – I'll be needing to "sneak" these in the dash some where. Where is the question. I don't want "pods" of things looking like rice cakes poking out of the a-pillers.

    I thought about sneaking it into the instrument cluster - but that requires a ton of work.

    How about INSIDE a hollowed out hazard or defrost switch? That would look pretty stock? Not to mention no cutting or drilling - just pop out one of the "blanks" and slide that puppy in. Yea that will do - can it fit? I bet it can.

    I happened to have a few extra switches lying around. Time to crack one open.



    They take some persuading to get them open. Two small screwdrivers does the trick.



    The 20 year old innards spill right out. All I care about is the front of the "bezel/case" and the front "button" - The button is a bit thick and dark, but I have a plan for that.



    So - about the only "display" you can squeeze into a hazard switch is a LED bar graph. Perfect for a simple gauge - I don't need a numeric display - just something much smarter than a dummy light - and something less than a laptop riding co-polit.

    A quick look at my boxes and boxes of parts lead me to the venerable LM3914. It's a linear LED driver. Basically you tell it the limits of the signal it will receive, and then you feed it a signal, and it can drive 10 leds to make a guage.



    It's made by National Semiconductor - and it's pretty fool proof. In testing it - I threw 20 volts on it's input pin, and everything else to see if I could fry it - no go - it's a trooper.

    Next step - pull out the parts - I have dozens of boxes like this.



    Fast forward to some internet searches on the LM3914 and I'm 90% there - throw in a diode to protect the circuit, and some capacitors to filter the nasty input voltage of a car, and a few more for good measure (too complicated to explain)



    After a few hours, I have a good hand drawn diagram - time to fire up the rig...And I have it in the computer - this will help me in the VERY complex part of the project - making the circuit board.



    Now if this was 1992, I'd have to face one of these bad boys...



    I know the parts I need are in there somewhere!!!!



    Oh god - this could take for ever...Luckly - it's all on line...



    After some more research - I know EXACTLY what I want. I'll mock up the circuit - and cross my fingers...



    And it works!!! Ok - I made it look easy, it's not - it's a lot of work.



    Next up - is taking it from prototype to the real world.
    Last edited by george graves; 11-12-2014, 04:52 AM.
    Originally posted by Matt-B
    hey does anyone know anyone who gets upset and makes electronics?

    #2
    George, you have my attention.

    Luke

    Closing SOON!
    "LAST CHANCE FOR G.A.S." DEAL IS ON NOW

    Luke AT germanaudiospecialties DOT com or text 425-761-6450, or for quickest answers, call me at the shop 360-669-0398

    Thanks for 10 years of fun!

    Comment


      #3
      Cool location idea..
      My idea (or was it someone elses?) was to replace the checkpannel with an led/lcd pannel.. It would have 6 different read outs on it and would blink in case anything was out of paremeter (rear brake lights, or oil pressure to low, etc)

      Julien
      Build Threads:
      Pamela/Bella/Betty/325ix/5-Lug Seta/S60R/Miata ITB/Miata Turbo/Miata VVT/951/325xi-6

      Comment


        #4
        making a DIY air fuel ratio guage? a lot of people use the LM3914 chip for doing that.
        85 325e 2.7 ITB'd stroker

        Comment


          #5
          Originally posted by rs4pro3 View Post
          making a DIY air fuel ratio guage? a lot of people use the LM3914 chip for doing that.
          or is this for lateral g's?
          1989 Bronzit 325ia- Sold
          1986 Diamondschwarz Grey Market 325i Sport Mtech 1- Parted out
          1988 Delphin 327i- Sold
          1995 Cosmos M3- Current

          Comment


            #6
            whats it measure?
            e30sport.net
            '15 Porsche GT3 - 7-speed PDK - Daily Driver
            '86 325es - s54b32tu - 6-speed - Mtech 1
            '89 325is - m20b25 - 5-speed - Individual

            Comment


              #7
              Originally posted by Digitalwave
              I admire your ambition, but how is a couple of LEDs going to be useful? At least do a digital readout so you can have some degree of accuracy.
              I think it's a great idea- you're not really concerned with the numbers usually as a driver for most engine parameters. (He's not using it as a tach.) You're really more concerned with whether something's inside parameters, getting close to being outside parameters, or outside of them.

              OP- props to you man. I took a semester of Electrical Engineering, and was lost the entire semester.
              sigpic89 M3

              Comment


                #8
                +1 on the great idea! The VW crowd has something similar and they look great!



                Last edited by Mtriple; 12-10-2007, 01:17 PM.
                Originally posted by Simon S
                When a dream is a dream for too long - it becomes a fantasy..

                Comment


                  #9
                  ^typical...$600 in gauges, 20 year old Blowchunks pullout deck

                  Closing SOON!
                  "LAST CHANCE FOR G.A.S." DEAL IS ON NOW

                  Luke AT germanaudiospecialties DOT com or text 425-761-6450, or for quickest answers, call me at the shop 360-669-0398

                  Thanks for 10 years of fun!

                  Comment


                    #10
                    Yes, but its "period correct"...
                    Originally posted by Simon S
                    When a dream is a dream for too long - it becomes a fantasy..

                    Comment


                      #11
                      Originally posted by SuperDuper View Post
                      Yes, but its "period correct"...
                      oh yeah, like whitefaced gauges are "PC"....no wai, mang!

                      Closing SOON!
                      "LAST CHANCE FOR G.A.S." DEAL IS ON NOW

                      Luke AT germanaudiospecialties DOT com or text 425-761-6450, or for quickest answers, call me at the shop 360-669-0398

                      Thanks for 10 years of fun!

                      Comment


                        #12
                        Originally posted by SuperDuper View Post
                        That is really fuckin' cool.
                        Reminiscing...

                        Comment


                          #13
                          looks interesting - narrowband, wideband, adjustable? I actually have all this stuff lying around somewhere though if I wanted to make one - but I think I'd rather turn my econometer into an A/F or boost gauge.

                          Originally posted by StereoInstaller1 View Post
                          ^typical...$600 in gauges, 20 year old Blowchunks pullout deck
                          some of us don't really care about the stereo - my music comes from a 7000rpm inline 6. ;)
                          Build thread

                          Bimmerlabs

                          Comment


                            #14
                            Originally posted by nando View Post
                            but I think I'd rather turn my econometer into an A/F or boost gauge.
                            I want mine to be oil pressure. Or voltage, oil temperature or damn near anything that is actually useful!



                            Originally posted by nando View Post
                            some of us don't really care about the stereo - my music comes from a 7000rpm inline 6. ;)
                            BLASPHEMY!

                            Luke

                            Closing SOON!
                            "LAST CHANCE FOR G.A.S." DEAL IS ON NOW

                            Luke AT germanaudiospecialties DOT com or text 425-761-6450, or for quickest answers, call me at the shop 360-669-0398

                            Thanks for 10 years of fun!

                            Comment


                              #15
                              Originally posted by StereoInstaller1
                              I want mine to be oil pressure. Or voltage, oil temperature or damn near anything that is actually useful!
                              i hear ya there
                              -----Zen and the Art of e30 Maintenance - / - Zen TOC - / - Zen Summary

                              Comment

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