If you're like me, you're working on an arcade cabinet and waiting for buttons to arrive in the mail, and thinking to yourself, "gee, I sure love Pong, but there's no way I can bring down some paddle-slicing fury with a joystick." It's a common thought. It's also why I ultimately decided to include spinners (paddles) on my arcade machine. You can too, and here's how to do it for cheap.
1 old ball mouse
1 peanut butter lid (yes, really)
a bunch of small coins
some old Legos:
-1 four or six-peg axle
-2 small right-angle gears
-1 large wheel
-some spacer bits
Step 1: Cheap Spinner Interface
Old ball mice are a great cheap solution for spinners, like the ones for playing Breakout, Pong, and some non-ball-based driving games. Not only can you find them for free, but they don't require any drivers, and they come with two optical encoders (one per axis), so you can make controls for two players out of one mouse.
Just cut out the bare parts you need. That means keep the plastic that holds the encoder shaft in place, and try to leave enough extra to support the electronic bits. It doesn't hurt to have a good flat area to glue the whole thing down with either.
Step 2: Attach the Shaft Gear
It'd be nice if you could just extend the shaft, stick on a spinner, and call it done, but I tried that and it went horribly. Just not enough purchase to add on a rod. Instead, a right-angle gear will give us a compact, reliable connection.
Stick the gear on the shaft, leaving enough room for the mating gear. The tricky part is to keep the gear centered on the shaft. If you spin it while the glue is setting, you can tell what parts are off and gently correct them.
Step 3: Add the Electronic Bits
The mouse uses an infrared emitter and detector pair to tell what direction the wheel is spinning, and how fast it's turning. Which means that they are important and we should keep them.
Use a razor blade or rotary tool to relocate the section of circuit board with the optical parts. This helps ensure they're the same distance apart as they are meant to be, which turns out to be pretty crucial. Then use a few wires to solder the points back together. Finally, glue the whole thing down, taking care to keep everything aligned. You can leave the mouse plugged in while you do this to make sure that everything stays lined up.
Just be sure not to have the sun streaming in like I did, since that throws everything off.
Step 4: Make Spinners Better
We're going to give the spinners some heft to help them feel more expensive. They would work without this part, but they would feel a little off.
Lay down some pennies in the wheel before gluing to visualize the spacing. Glue them down in a star pattern to help keep the spacing even. Hot glue will let you stack 2 layers of pennies, super glue should be thin enough to stack 3. Fill up both sides for more weight.
Step 5: Glue on the Lid
What can I say, peanut butter lids just seem to be the right size. And for some reason, almost every brand in the US seems to use the same kind.
Put a ring of hot melt glue around the wheel, and stick the wheel in the lid. While the glue's hot, stick a few dimes in between the wheel and the lid to help keep everything centered.
Step 6: Paddle Assembly
First insert the paddle axle, then lego bracket (6 bar in the pic), spacers, side gear, the wheel/knob, then finally the whole mouse gut assembly.
Step 7: Paddle Installation
Let's put all the parts in the machine. I stuck everything together on the front panel, then glued in the electronics once the panel was in place. In retrospect, it would've been simpler to assemble everything on the panel, electronics and all.
I used a couple scraps of MDF as a platform for the mouse parts.
If you keep the mouse plugged in while you install the paddles, you can make sure everything stays working as the glue sets.
One great thing about hot glue is that you can sort of control the working time of it by varying the temperature of the glue gun.
Step 8: Use Them!
For bonus points, add some black or chrome contact paper to the lid to make it less lid-like.
MAME supports a bunch of spinner-related games, but sadly, Pong is not one of them. You'll have to search for some sort of support for games that don't fit in, misfits, if you will.