I'm making a adventure map and a need to activate a command block and at the same time have a piston door open, but the command blocks need the switch to be on to activate. The pistons need the switch off to reveal an room. I need a way to make the sticky pistons close when touching power.
Use redstone torches. If you put one on the other side of a block with redstone facing it, it turns off, like this: I recommend building something like this (You may need to change it a bit to fit your map): If you have any problems, or need further help, just let me know in the comments for this answer.
Good luck on your map!