Evan writes, “While writing the article on multiplexing the esp’s inputs I came up with the idea of PWMing all the outputs at once by interrupting the path to ground with an n-FET. That’s actually not a bad idea, and I have an extra input on the analog MUX that I can use for a light sensor so I can even have auto-dimming. This is to describe how I did that.”
More info at Evan’s Techie blog.