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Need electronic help with a custom transmission shifter

Discussion in 'General Electronics Discussion' started by SinisterSF, Jan 4, 2018.

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  1. SinisterSF

    SinisterSF

    2
    0
    Jan 4, 2018
    Hi,
    I build custom classic cars and I regularly dabble with normal electronics in a car but I want to build something a little abnormal. A lot of new cars have gone away from a shifter cable attached to a shifter lever. Land Rover, Jaguar, Mercedes and many others have dials and buttons that send an electronic signal to a servo or actuator that turns the lever on the side of a transmission to shift it into gear. There are crazy expensive kits that do this but they're ugly and meant more for racing. I attached a picture of the kind of dial I want to use, I hooked up power to it and I can see that power comes out of specific terminals based on where the dial is turned to. I want to setup an actuator or servo that will push or turn the transmission lever to one of the 4 different positions based on where the knob is turned.

    Thanks!
    s-l1600.jpg trans.jpg Dial shifter.jpg s-l1600.jpg trans.jpg Dial shifter.jpg
     
  2. Bluejets

    Bluejets

    4,662
    984
    Oct 5, 2014
    Your actual selector shows 5 position but your diagram shows only 4.
    However, one arrangement would be a microcontroller, with each of your selector terminals going to a digital input.
    Servo output with position based on a pre-programmed output position.

    That would be just a starter. One would have to decide how the go/no go gate would operate and program that via sensors or it may well have to be a mechanical requirement ( say like emergency stop on machinery).

    In any case it would require quite a lot of thought and logic conversion as well as programming ability.
    I think you will quickly see why things like this are "crazy expensive".
    No one is going to put all this effort in for nothing if you get my drift.
    But doable if you set your mind to it.

    Trouble is with some microcontrollers, especially the "hobby" variety, have limited use clauses.
    If the machinery is to be used "on the road" it may also be a nightmare to navigate many laws.
     
    Harald Kapp likes this.
  3. Harald Kapp

    Harald Kapp Moderator Moderator

    11,310
    2,588
    Nov 17, 2011
    You'll have to incorporate many fail safe features to prevent e.g. shifting from full forward into reverse while driving, shifting into a gear while neutral is selected etc. You'll have to make the circuit very EMC proof to avoid reset of the circuit due to an EMC event (e.g. a load dump on the car's battery supply).
    You'll have to select components rated for automotive use (especially in terms of temperature range).
    You'll have to get your setup certified to be allowed to use it on public roads (Bluejets already mentioned that).

    If you're dedicated to cut your path through that jungle, it can be done.
    My personal recommendation is to go for an off the shelf solution with all these obstacles already shoved out of the way.
     
  4. kellys_eye

    kellys_eye

    4,275
    1,147
    Jun 25, 2010
    I agree with Harald (above).

    Limit your design to changing the appearance of the commercial product - some wacky-looking, flashy-light/digital display mods etc - as trying to attempt the whole procedure is far too complicated/expensive.
     
  5. SinisterSF

    SinisterSF

    2
    0
    Jan 4, 2018
    Lots of points I hadn't thought of. The 5th point on the dial is for a manual shift mode which I'll just omit. I hadn't thought about the programming with this, I've never made something like this. It sounds like a ton of work, but work I'd be more than willing to play with. I think I'll wait until I've got a firm grasp on this before I dedicate it to application in one of my cars. I'm retiring from the military next year and am planning to take some electronics and robotics classes next year so perhaps I'll shelf it until then so I've got the basic knowledge. Hell I can probably use this as a project in the class.
     
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