Could you give me some advice on how to carry out a project that involves:
1 - one entry in 230VAC
2 - which powers a 230VAC/12VCD converter (IRM) in 12VDC for a fan (off board) and
3 -which also powers a 230VAC / 5VDC (IRM) converter for an arduino board and its modules and 2 230V relays driven by Arduino to power 2 lamps (off board).
Should I make 1 single card or 2 or 3?
I have the impression that the easiest way is to make a single map paying attention to distances (creepage and clearance).
Or NOT.
Converters are pretty available. Printers, tv’s, laptop computers don’t bother with integrated solutions. I’ve given up on ‘cuz I wanna’ to being more practical myself. What if the 230VAC part of the board goes haywire? Now you have to fix the board or have it made again. With an external converter, you simply get a new one. Lots of worry removed and probably at a cost savings.
Generally AC/DC converters have plenty of clearance between the HV and LV sides, so you can place them at the edge of the board and not worry about the HV.
There are many other issues if you are designing a product that needs UL or CE approval, but for personal use, I wouldn’t bother making two boards.
If the relays are controlled by the Arduino then you still don’t need the 230V on board. Just at relay in, relay out. But, then again, I don’t know the whole design or components.
This is a completely separate circuit and you will have to power it off board regardless. But, we are getting beyond the scope of Kicad here. This is basic design options.
I’ve done this many times - it’s a commonly-done thing and sort of Basic Electronics stuff and nothing to do with Kicad…
That said, here’s example of one of my many Hydroponic Water Pump boards (pushes out 12Vdc through Relay-Switch (controlled by Arduino Nano’s 5vdc Pin - the 12V also powers the Nano)
LED’s under the Yellow cover
I also have similar designs that bring in 120VAC, step it down to 12VDC at 2A and push it through Relay Switches…
230V (or even 115V) is deadly and from what you have said so far it sounds way above your capabilities. That may sound harsh but it is way more than just creepage and clearance. Even a bare relay board like you linked is a dangerous item. You could buy an off-the-shelf relay sealed in an enclosure with a low-voltage control line, or, I agree with @hermit, just NOT.
@alvaro562003 Take none of this personally. I have college training because my employer paid for it but EE was never my field. What I learned in school didn’t even come close to preparing me for the ‘actually doing it part’. I got back into it through Arduino myself. This has proved to be an entry point for lots of folks recently. So, when we see Arduino and 230V in the same post it is cause for concern. Theory versus practice still bites experienced EE’s.
If you look at the project you will see that relay doesn’t have to be on your board. Therefore, 230V doesn’t have to be on your board. It can enter and exit via the relay. At least that’s the way it looks too me.
The specific’s of the circuit below aren’t important, what is important is understanding that some Relays contain Two Independent Switches, thus can pass Two input power’s (per Relay’s specification).
The Switches can be NO(Normally Open) and NC(Normally Closed) and the switching is controlled On/Off by a Coil that is activated by an Arduino, for example…
So, deciding if On-Board power or bringing it into the board from outside through Connectors, Terminal-Screws/Posts, Soldered-to-Pads…etc is part of the Design decisions…
Example shows this - I used Net and Global Labels for fun but, which to use in real circuit depends on Design Decision’s…
