@EricLegend. We exclude this pin because Raspi IO doesn't support talking to WS2812's. To talk to WS2812's, you'll need to use an independent library. By default, Raspi IO controlls all pins on the Raspberry Pi in such a way that it prevents other libraries from using the pins too. To allow the node-rpi-ws281x-native module to access GPIO18, you need to tell Raspi IO to not control that one pin so the other library can.