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Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
@Gordon
Ahh, sorry, you're totally right. Pins need to be 5v tolerant, or the relay has trouble turning off. I vaguely remember that some work and some don't.
To fix it without using 5v tolerant pins, you could disconnect the jumper that's usually on the relay board and supply 3.3v to the data side of it, but 5v to the relay itself.