So it may have a minimum current requirement to stay in regulation.
It may be non-isolated which is bad
It may have high ripple voltage.
I will try to look for a different module with datasheet
Good idea or you can buy a bunch of modules and test them, then throw away the bad ones.
Why would you buy a 5V regulator?
Any phone charger will deliver 5V 2A.
Use an old one from the drawer with the rats nest of cables!
The print has 220VAC tracks close to the 5VDC tracks.
Not good!
Look at the red boards later in the thread.
5VDC connections on one side
220VAC on the other side
Much better!
Because I wanted to "save" the extra plug.. but I might just do so.. (?)
If you think that two relays in series can switch 2x120VAC=240 VAC, you should not work on this project without supervision.
This not what I thought. I thought about two relay - one for each wire. But I just do it with one relay..
Could you explain, why do you think you need an "extra" plug in case you use a phone charger and no extra plug in case of above modules?
As long as that relay is rated 240 VAC, it is fine!
Because with the above module (220VAC to 5VDC), the conversion is made inside the box, so there's only 1 plug from the wall to the box.
How much current would each one be switching ?
Think carefully before you answer
Each relay would be switching the same current — the load full current, since they'd both be in series with the same single load isn't it?
I will go with one relay only to switch the Line wire
Your answer is correct so I assume that you have realised that 2 relays in series, each with half the current switching capability, would not be a good idea,
the same as with phone charger....
Absolutely switch the live and neutral using a double pole type. Doesn't need to be changeover.
Older UK domestic socket outlets used to be single pole, but many turned out to be wired to switch the neutral, leaving the live still connected.
Double pole outlets were introduced to completely isolate the consumer side, even if incorrectly wired. And yes, I have seen live and neutral wired the wrong way round, on a 10-kW shower heater.
Without checking, there's a requirement for a minimum clearance, often an air gap, of 3-mm on PCBs, between the HV side and the LV side.
It's all done for safety.
Either module can power an Arduino Nano reliably. Both provide regulated 5V output. Connect the module directly to the Nano's 5V pin. Don't use VIN here. The Nano needs little current. Even the 1A module offers plenty. The 2A version gives extra headroom. That's useful for relays and future additions. Since you're switching mains, choose an isolated, reputable AC-DC module. Add an input fuse. Use a proper insulated enclosure. Maintain safe clearance between mains and low-voltage wiring. Your clap-switch project can run from this single supply. That eliminates the extra USB adapter completely. Also, use an appropriate mains plug and wiring method. Unikeyic's guide on electrical plug connector types explains common standards and connector choices explains common standards and connector choices:
https://www.unikeyic.com/blog/electrical-plug-connector-types.html
Since you're powering your setup from the main line, it is important for you . Safety matters more than saving a power brick.
Sorry but I won't recommend or disapprove of any product unless I can find and review the manufacture's official datasheet or instruction manual or have actually used the product.
Can you buy from Digi-Key, Mouser or another major electronic parts manufacturer?