Connectiong 2 arduino relay (A000110) shield modules

Hi there,

For one of the projects I'm working now I will be needing to extend current relays available from 4 to 8. I have already one Arduino relay shield A000110.
I was wondering if it is possible to add another A000110 shield to increase the no. of relays.
If someone did this before I would appreciate some guidance.


Hi and welcome to the official Arduino forum.

You have to "hack" that shield to be able to do so.
The shield is hard-wired to pins 4,7,8 and 12, an incredible poor choice of pins (12 is part of a very popular bus).
Not being able to select the pins you want is also a poor choice of the producer of this product.

So now you can't simply stack 2 of these shields.
The 2nd. shield can be connected using jumper wires.
That has the advantage that you can jumper any Arduino pin to any shield-pin.
Of course you shouldn't forget to connect the power pins, or else nothing will happen.

You have asked your question on the official Arduino forum, probably believing that you have bought a product from the same guys.
But that isn't the case, you've been duped by a very nasty battle for the big bucks.
That company seems to have the rights to the name "Arduino" in the USA but that is still in dispute.
You can see a difference in the logo: over here the logo is put in a dot, over there it's in a square.

You're still welcome over here with your questions, but you also have the right to know about this mess.
And by buying stuff over there, you aren't supporting this community in any way (just telling so you know about that too).

Thanks for the update on this. I didn't had a clue about this.
The shield I got it as a present a while ago, I was the "breadboard".
I saw some nice 8 relays modules that I will study in the next days that can be much easy connected to Arduino Mega board.
Any advice is appreciated