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By Igor Mendes
#94096 Hi everyone!

I'm working on a project where a NodeMCU will be inside a switch box. To power it, I was planning on using something like this https://www.amazon.com/HI-Link-HLK-PM01-Step-Down-Intelligent-Household/dp/B00ZUELJ6K (Hlk-pm01). My questions are: to power the NodeMCU, is it simple as connecting the Hlk-pm01 to the power grid and to the NodeMCU board? Is it safe to do so?

I ask this, because I have seen some projects where people use fuses and capacitor as overload circuitry, like this one. Is it really necessary for this overload protection? Or is it fine to hook up just the Hlk-pm01? I'm mostly worried about safety (don't want to start a fire since the board will be inside a wall switch box) and size (not much spaxe inside a switch box). Also, is there any other way to power the board that's size efficient and simple? Something for which I would not need to worry about circuitry protection and all? Like a really small usb power supply?

What I'm trying to achieve with this project is turning a regular wall switch into a wireless smart one!
Thanks!
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By bra1n
#94103 I've been using them for a while without issues, just take the usual precautions with separation of mains and low voltage circuitry when wiring them up.
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By Inq720
#94104 https://www.amazon.com/HI-Link-HLK-PM01-Step-Down-Intelligent-Household/dp/B00ZUELJ6K
Has anyone had the opportunity to crack one of these open? It looks sealed versus having screws to open.
I'm wondering if the protection is a one-shot deal (fuse) or some circuitry that resets.

I also have wondered about powering projects, and use these type of adapters.
https://www.ebay.com/itm/353254047204 but have not tried to squeeze one into a wall box.

Some of the early LED bulbs have circuitry. I haven't studied one yet, but it would need safety circuitry. Anyone with experience with these???