Has anyone used these? Will 2 of them significantly reduce the battery power / time of the 9V battery? If so, are there any other ways of doing the above?
as both the poles are connected
dc42 - Thanks, I understand that. The only thing I'd be concerned using your suggestion is the 9V connection going straight to the i/o pin / ground, as both the poles are connected - would this not break the board? If so, should I just put a resistor on the i/o connections, or do something similar to SW Scotland's idea?