A little background: I'm hoping to take the PWM from the Disney Parks Made with Magic Ears in order to drive a short 12V strip of LEDs (Here's a teardown.) After taking a pair apart and testing, I know the tri color LED is being driven by 1.6 V ( I was also able to wire another RGB LED in series). From what I've read, the LED Amplifier will boost 3-5V signals to 12 V.

My thought is something like a MOSFET or WLED driver would work? I'm also concerned about too much current through the existing ear circuit.

Any guidance would be appreciated!

Here's the the circuit so far.

  • \$\begingroup\$ Which led amplifier are you using? \$\endgroup\$
    – Passerby
    Mar 24, 2015 at 3:06
  • \$\begingroup\$ I was just about to add that (two link limit) \$\endgroup\$
    – eburch
    Mar 24, 2015 at 3:07
  • \$\begingroup\$ And then hit enter too soon. I'm using these \$\endgroup\$
    – eburch
    Mar 24, 2015 at 3:08

1 Answer 1


I haven't tested this, and its off the top of my head, but based on http://www.stuffandymakes.com/blog/2012/07/08/disney-glow-with-the-show-ears-teardown the LEDs are common anode with the microcontroller sinking current (open drain). Using a optocoupler on each line, with the led amp providing the power switching, you should get exactly what you want. All you need is the optocoupler in between vcc and the rgb led (one per color).


simulate this circuit – Schematic created using CircuitLab

  • \$\begingroup\$ Thanks Passerby! I've never heard of an optocoupler before. Would something like this work? \$\endgroup\$
    – eburch
    Mar 24, 2015 at 15:23
  • \$\begingroup\$ Yes. The optó is essentially just an led and a photo transistor, but in this case it helps prevent inverted logic (inverted colors). And it's really used for signaling so the current capacity isn't an issue \$\endgroup\$
    – Passerby
    Mar 24, 2015 at 16:19

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