I'm thinking of using something like this: https://www.amazon.ca/Dolity-Converter-Isolated-Switching-Transformer/dp/B07CSZ1174?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duc12-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B07CSZ1174

or this: https://www.amazon.ca/Voltage-Regulator-Converter-Transformer-Protection/dp/B07LC1C4ZZ?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duc12-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B07LC1C4ZZ

to power my arduino.

The reason for this is I have a contained box with a few pieces of equipment (all on ac power) controlled by an Uno. There is a single AC power cord (North American) running from the box to power the whole unit. Obviously this just leaves the Uno.

Sure the standard 5V barrel adapter prongs could be shrink wrapped to the raw AC wires but that's not very clean. I was imagining a module like those converters that could be wired into the VIN pin and gnd after converting the AC input from the main power line going to the box.

The uno is powering an ethernet shield, 4 port relay, sht20 sensor, mh-z16 sensor, and 16x2 lcd display.

Thoughts? Honestly this isn't really my call. My boss doesn't want any plugs or standard outlets inside the box. It's like he only wants it to be formal circuit boards and soldering. No shrink wrap or electrical tape. Yes I realize standard adapters that plug into a wall are already at a price that won't be possible to beat.

  • I highly aggree with @Majenko. Any old USB phone charger would make a safer and also cheaper power source for your Arduino. – Kwasmich Mar 8 '19 at 14:56

Sure the standard 5V barrel adapter prongs could be shrink wrapped to the raw AC wires but that's not very clean.

Also very deadly. DO NOT DO THIS!!!! The Arduino will explode (literally. I am NOT joking here!!!) and potentially electrocute you.

Those modules you show are not "buck" regulators. They are SMPS modules - an entirely different thing.

Yes, one of those would be suitable for powering an Arduino from a mains supply, but given your supposition above I rather suspect your skills and knowledge would make wiring it up a dangerous prospect.

Better would be to use a proper off-the-shelf power plug and have someone qualified install a suitable socket inside the enclosure.

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