moondog
It's an obsession but it's pleasin'
I have to take back what I said. For the life of me, I can not get the hopper to fire blue lights with an external battery without the back end in the loop. There is something very cool happening in there and I too have no earthly idea how it works.
Nothing I have checked on the back end with a meter, makes any sense to me.
Maybe somone with better electrical skills can crack it.
These guys figured it out for you: