feasibility of transfering power via coils for lighting LEDs?

Discussion in 'The Projects Forum' started by Johnnz, Jan 27, 2010.

  1. Johnnz

    Thread Starter Active Member

    Dec 31, 2008
    Hi all,
    been away for a while but am now back and restarting work on my HDD based audio player. I want to have a scroll wheel (approx 60mm diameter) to select songs and am investigating ways I can use to light the wheel with small leds inside the dial/wheel (purely for cosmetic reasons). The wheel will be on the front face of the player so that the axis of rotation points to the user.
    Recently, I dismantled an old VCR and noted how the video heads embedded in the shiny silver flywheel transfer their information via coils in the spinning drum to ones fixed outside.
    Unfortunatly I couldn't get the coils out in one piece, but I am wondering if I were to make coils similar to this I could transfer enough power to light 4 or more LEDs inside my wooden scroll wheel?
  2. Wendy


    Mar 24, 2008
  3. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    An alternate idea woudl be use a hollow/tubular spindle for the scrollwheel and run bits of optical fibre from each illumination point to a bundle in the spindle.

    Fit a fixed ultra-bright LED against the back of the spindle so all the fibres are illuminated.

    It would take a bit of mechanics and possibly a belt or gear drive to the encoder? you are using to sense the scroll wheel, but waay simpler than inductive power transfer.
  4. Johnnz

    Thread Starter Active Member

    Dec 31, 2008
    Yes, an alternative method may well be simpler . I have thought it may well be a lot easier to simply backlight through the scroll wheel. If I drilled holes around the outside of the wheel (like dots on a clock face) and filled them with a clear or slightly milky epoxy then sanded off smooth to the front of the wheel, LEDs could be fixed in behind the wheel away from the center/ axis of rotation and directly in line with the epoxy filled holes to provide illumination.

    An have also thought of buying an old electric toothbrush and using the charging coils out of it. Presumbly the power would be adequate to light LEDs with, so may experiment with that too.

    Will have a read through the thread Bill linked to too though. Thanks for that.