TwinTurbo.NET: Nissan 300ZX forum - Clock/Ethanol content gauge replacement
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Subject Clock/Ethanol content gauge replacement
     
Posted by Captconan on December 15, 2020 at 2:37 PM
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Message I have a flex fuel setup on my Z32, with the standard GM style ethanol sensor going to my Haltech (did not buy the Haltech part because it's marked up so much), and from there it adjusts the fuel maps and boost on the fly etc. Nothing groundbreaking there. However I had no gauge to see what my ethanol content was without using my laptop to login to the Haltech and view it that way. I looked around for stand alone E gauges, and didn't find much. The packages I did find included the sensor and the gauge, and would run upwwards of $150 or more, which I wasn't interested in.
So, what are the options here for a gauge? I'm already using my center console pod for vac/boost, AFR and Fuel Pressure. I need to install a gauge in some other creative way. Cue the clock.
Being the 3rd or 4th owner of the car, the wiring behind the center console was a complete quagmire of bad soldering, butt splices, different gauge wiring, modifications, exposed copper and just a general mess. The clock still worked, but I really have no use for a clock between my wristwatch and cell phone. Can I modify this clock LED to display E content? Completely not worth it. There is a better way.
Ethanol content is measured using a circuit that outputs a frequency of 50-150Hz depending on a E% of 0 to 100%. This Digital pulsed input is what the Haltech is measuring, and what I need to piggyback on to get a functional gauge.
Using an Adafruit 4 segment alpha numeric display, a cheap Arduino style microcontroller, a few resistors and a solderboard, I was able to program and create a new LED display that fit perfectly in the old housing, and tapped the frequency signal to display a random predefined scrolling greeting message followed by the E content.
I'm very pleased with this result. The clock function is gone for now, which doesn't bother me. Would anyone else be interested in this??
https://www.youtube.com/watch?v=l1PJh-f7yHA&ab_channel=captconan5

https://imgur.com/gallery/pQCd2pU

     
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