New output plugin request: PWM GPIO

[gaijinsr]

Hi Frans-Willem, I like EspLightNode very much and it works great for me, thank you for sharing your work! I have a request that I think would be rather quick for you to implement (it would take me much longer) and which could be useful to many people: There are a lot of those "H801" ESP8266-based LED contollers around, they control 5 channels via PWM on the GPIOs 12,13,15 (RGB), 14,4 (W,WW), plus two LEDs on GPIOs 5,1. It would be great to have an output plugin that writes the values of the first seven DMX channels to the GPIOs listed above as PWM, this way EspLightNode could also be used to control dumb LED strips. Best, Stefan