Relay Shield Module

Has anyone used the relay shield modules for Arduino?

Are the relays noisy/ make clicking sounds, and can you stack two modules to control 8 relays?


You could start providing a link to the product.

Good Point!
Here is the link:

No experience with them. I found the schematic on this site

It uses 4 fixed pins to control the relays; this implies that you will have to hack it if you want to stack two on top of the Arduino.
It uses the 5V of the Arduino; when a relay is activated, it will initially draw quite a bit of current and the Arduino might reset. Therefore I would not buy it (although the relays might be low power types and the problem might not be as big as I have presented it].