In this upgrade from my B3 Blinking Business card Badge, I upgraded the LED to RGB since I figured I would be able to change the color, but I forgot to check the harvested voltage, so the only one you can see when powered by NFC is the red LED.  The 1.8V generated inside the LPC8N04 will not turn on the blue or green.  In my next project I will add a capacitor and schottky diode so I can double the voltage by toggling an I/O.