If you haven't watched this video:
Then I'd recommend doing that first or else this won't really make sense.
Now, these instructions are going to show you exactly how I made the Rhythmic Wii Remote Presser, not necessarily the best way to build it. So feel free to change any part that looks really messy. (I was improvising the entire thing)
You'll need a fair variety of LEGO bricks and technics for this to work. I'd look ahead to see what parts exactly you'll need (a list of which I'm not including due to too much variety), but if you don't have an NXT (LEGO robot) then this instructable is of no help to you...unless you want to attach a wheel and spin that (which I would not recommend).
Here's a list of basic supplies:
-LEGO bricks and technics
-LEGO NXT & motor
-Wii Remotes (2 of them)
Step 1: Getting the Wii Remotes to Sit Still
The very first thing I'd do is attach your Wii remotes together with a rubber band about in the middle. This just insures that they'll stay together.
Now, just look at the pictures and build what you see (or close).
This step is very flexible, so do what you can to keep the remotes in place.
Step 2: More Wall
Same thing here, just follow the pictures.
NOTE: The two bricks at the end can be replaced for something much smaller and stronger.
Step 3: The Button Presser
This will be the thing that makes contact with the buttons. Just follow the pictures.
(The tooth on the left one doesn't need to be a tooth).
Step 4: "The Button Presser" Presser
This is what moves the button presser in the previous step. Just follow the pictures as usual.
Step 5: Adding Restraints
This machine would be useless without restraints. Put the string on just tight enough over the pole so that when you spin the gears, the buttons get pressed.
The wire keeps the connector from coming apart.
Step 6: Powering Your Machine
Now you're ready for some results. Just download the NXT program (if you haven't already) and put a move block out with the right motor port selected, and the direction going the right way.
The amount of power necessary will vary a whole bunch. I had to change it every time I used it!
And the motor can just rest on the ground.
Step 7: D-Pad Holder
You may want this if you're going to leave this running for a while while the D-Pad is held down. Just do what you see in the pictures.
Step 8: Conclusion
The main reason I built this was for Kirby's Epic Yarn, but I'm sure it
could be used for a lot of other things that require timed inputs.
By the way, this thing gets really noisy, so I'd recommend putting a box over it to muffle the sound a little.
And with that, good luck and happy game breaking!