This may be more suited towards the Elec engineering SE, but thought I'd ask here as I'm working with the Pi.
I recently picked up this relay board, and soldered it all together using their guide, however it seems not to be working, that is when I run
i2cdetect y - 1 it doesn't show anything in the 0x20 cell, which I think means the relay isn't connecting to the pi?
How do I go about debugging what the problem could be? I presume I'll have to start testing individual components to see if any of them have blown? Can that be done on the board itself, or will I have to un-solder the components?
If it impacts at all, when I first connected the pi to the relay via the ribbon cable, I accidentally connected it upside down (the red-strip was not at the top of the pi, where the 5v pin is)