Rotary encoder controled TV remote control help needed

Discussion in 'The Projects Forum' started by SD40T-2, Oct 5, 2009.

  1. SD40T-2

    Thread Starter New Member

    Oct 5, 2009
    Greetings to all,

    I have a elderly grandmother who is getting to that point in her life where things need to be extremely simple or she can't understand, interface or use them. The June HDTV only / analog retirement event has made watching TV for her almost impossible. My father purchased converter boxes for her but she's unable to operate them in conjunction with the TV and usually she gets the TV off of channel "3" and then there no hope of her getting things back short of us driving to her house and resetting things back to the way she needs them.

    On of the things that seems to becoming an issue is the simple use of a remote control. My father insists she can't distinguish the difference between 'short' momentary presses for channel changes and longer "hold down" presses for volume adjustments.

    To that end, I'm proposing buying a HDTV ready TV. Purchase a simple "Large button" universal remote. My thought was to dissemble the remote, tap off the contact pad pins/traces for the volume UP & DOWN and Channel UP & DOWN and interface them to a pair of respective rotary encoders with big knobs for her ease of use. A turn up (CW) of the knob would make the volume go up and a turn down (CCW) would make the volume go down and likewise with the channel knob. That's all the interfacing she would need other than perhaps mute and Power.

    My knowledge of rotary encoders is very limited but from what I've read I'm assuming that I would need an 'incremental' type of encoder..correct? I also don't know what type of interfacing circuit I may need to build that would be applicable in this situation.

    I'm also interested if different configurations of decoders would give longer rotational angles between each encoder "signal" transmitted. Her ability to maintain fine control isn't there anymore.

    A couple of concerns I had was: 1. I'd need the encoders to function in such a way that if she turned the encoder too slowly or held it between detent that the remote would continue to send the respective command and make the channels continually change or race the volume up to full, etc. 2. My other concern I had is that any type of auxiliary circuit to interface the encoders to the remote would prematuraly wear down the batteries in the remote if it had to be active full time. I'm assuming that some kind of CMOS logic may be the answer in this case.

    Thanks in advance
    Last edited: Oct 5, 2009
  2. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    Look for Quadrature encoders.