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Discussion in 'Microcontrollers, Programming and IoT' started by Lsxiroc85, Jul 3, 2013.

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  1. Lsxiroc85

    Lsxiroc85

    2
    0
    Jul 3, 2013
    Okay here is what I'm doing sorry if I post this in the wrong spot but, I have a transmission for my car that I can hook switches up to to shift it but here is what I want to do. It's a 4 speed and I want to build a computer or something that will allow me to hit one button to shift up and another to shift down. Like a paddle shifter. But I can't find anything on how to build anything that would work. The trans has two solenoids to shift it. Sel A and a sel B. sel A on and Sel B off is first. Both off is second gear. A off and B on is third and both on is forth. I want to select them with just two buttons. One for up shift and one for down shift in order. Any ideas about how to do this?
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    11,517
    2,652
    Nov 17, 2011
    Google binary up/down counter.
     
  3. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    This can be done with a four position switch and some diodes.

    You will need a mechanical arrangement to move the switch one way when one paddle is pressed and it should be moved the other way when the other paddle is pressed.

    This would eliminate electronics at the expense of mechanical complexity.
     
  4. stoveitin

    stoveitin

    16
    0
    Jul 3, 2013
    or if your into microcontrollers you could use a arduino, atmel or pic to write a simple program to do it for you they would be easy to learn to do. Also with this option you could program it to do more advanced things with your gears.
     
  5. Lsxiroc85

    Lsxiroc85

    2
    0
    Jul 3, 2013
    The binary chip won't do what I need it to do. The outputs keep reselecting there self before it goes to the next. That chip would be like 1st gear then 2 gear then first again second then third then first again then second etc. the mechanical way would work with a four way switch but I can't figure a way to do it. Thought about a stepper motor but still have to program that. And I've been looking at arduino but I've never wrote a program before like that and wouldn't know how to begin for something like this.
     
  6. Harald Kapp

    Harald Kapp Moderator Moderator

    11,517
    2,652
    Nov 17, 2011
    In tabular form:
    Code:
    A   B   gear
    1   0    1
    0   0    2
    0   1    3
    1   1    4
    What the counter does:
    Code:
    C   D   count -> gear -> required   A   B
    1   0    2    ->     3    ->        0   1
    0   0    0    ->     1    ->        1   0
    0   1    1    ->     2    ->        0   0
    1   1    3    ->     4    ->        1   1
    You could build a decoder to convert the counter's output to the required shift commands. This will require a handfull of logic gates:
    A = (C and D) or (notC and not D) = not (C exor D)
    B = (C and not D) or (C and D) = C -> no gate required
    (I hope I did get my tables right :) )

    Or, as stoveitin suggested, use a microcontroller.
     
  7. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    If you go the switch route to energise the solenoids, put the supply on the common terminal.
    Using Harald's table, connect the outputs as follows.

    gear 1 connect to A
    gear 2 no connection
    gear 3 connect to B
    gear 4 connect to two diodes, one going to A, the other to B.

    The diodes are there to stop cross connection between A and B when only one solenoid is needed to be actuated.
     
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