Difference wiring relay board 8 channel vs 16 channel

[aawsum]

@Wawa

These relay boards are activated when the Arduino pin is LOW.
That's why you set the pins HIGH in setup(), to de-activate the relays on bootup

yes this I figured as all relays turned active when powering the board without arduino attached.

For the 16 channel relay board I wired the 5v back to the arduino.
When I power the arduino and then power the adapter to the relay it looks to be all fine.
functionally of flipping the relays (active/not active) seems to work fine.

Thanks for the active discussion on this, really helpfull!

[Wawa]

@aawsum

When I power the arduino and then power the adapter to the relay it looks to be all fine.

Not needed if you follow my advice (post#24).
That setup code configures and leaves all relay pins HIGH (relays not activated).
Your loop() code should then be written for active LOW.
Leo..

[aawsum]

I understand but as I mentioned in my earlier posts the code on the arduino has not been written by me this time.

It is ok, I think it runs fine in this setup.

Thanks for the advice though.