Replace tact switches with a rotary encoder for volume control.

Discussion in 'General Electronics Chat' started by public-pervert, Apr 24, 2015.

  1. public-pervert

    Thread Starter New Member

    Apr 24, 2015
    Hello everyone!

    I'm working on this project: I'm basically installing an iPad mini on the dash of my new car, but I'm facing a problem: The iPad doesn't offer volume control when it's in Dock Mode and the head unit will be hidden behind the Tablet. So I modded a remote controller to put external controls and the IR is on a place where the radio can "see" it. I actually put a little multi directional tact switch to control the volume, but it is faulty. It works sometimes, but sometimes it goes crazy and keeps turning the volume up. I know that are the multi directional tact the problem as it works normally with other tact switches. No shorts aswell as I've tested and retested it with my multimeter. The big problem is that I just can't find a replacement for it. No one sells 4 way tact switches here (Brazil), no matter how much you search. A point I need to mention here, is that isn't just touch the volume signal on the ground for it to work. The controller uses some kind of combination of pins on the main IC, but both the volume up and down have a commom pin.

    So here goes the question: Is it possible to replace the tact switches with a rotary encoder? I really dont want poor tact switches on a mod like that. A rotary encoder would look so much better. Is there a "simple" way to do it?
  2. pwdixon


    Oct 11, 2012
    I think you'd need a processor to read the encoder and then output the appropriate tactile key press equivalents.

    Have you tried ebay for a part similar to the original?

    By the way, as this is a car question someone will come along soon and terminate this thread as car questions are not allowed on this forum.
  3. AnalogKid

    Distinguished Member

    Aug 1, 2013
    There are many different kinds, but the most basic multi-position tact switch is just 4 separate switches in one package with one knob. When you push it to the up position, for example, it does not make a string of "up" commands or pulses. It is a spst switch, so it just sits there closed until you release it. It is the system electronics that interpret a switch that is closed for a certain period of time as a request to constantly increase whatever it is until the switch is released. So a rotary encoder won't do this without some new electronics as an interface circuit.

    If, on the other hand, you increase the volume by repeatedly pushing the switch rather than one push and hold, then a much more simple circuit can adapt the output of a rotary encoder into two signals, a string of "up" pulses when turned one way, and a string of "down" pulses when turned the other way.

  4. public-pervert

    Thread Starter New Member

    Apr 24, 2015
    I've read the forum rules and see that cars questions isn't allowed, but this is an electronic related question as I'm modding an electronic system to install it later on my car. Maybe sounds confusing, but I don't see it as a car question.

    I'm talking about mechanical encoders by the way, not the optical ones. They have three pins, one is commom between the other two, and it momentarilly touchs the pins with the commom as you rotate it. That's why I think it maybe could not be that complicated. I haven't tried ebay, as things take forever to arrive on my country.

    @AnalogKid I know about the multi directional tacts. The controller originally uses normal carbon rubber switches. I wired the multi directional switch by hand on the corresponding pins. The volume works both keeping it pressed or repeatedly pressing.

    Any ideas?

    Thanks for the replys, by the way.