Whether it is a screaming doorknocker, a Frankenstein dancing to the monster mash, a rat with glowing eyes or an animated witch, using a battery interrupter can transform a simple toy into a fun treat with a seasonal flair.
There are two ways you can do the battery interrupting. One way is to get a thin piece of copper metal and using snips or scissors, cut it in a circle or square about the size of a dime.
Using speaker wire, solder one of each of the two wires to either side of the copper plate. The other end needs to have the wires soldered to a 3.5 mini jack plug that you can buy at Radio Shack or at a computer electronics shop.
The following tutorial will give you some pictures and directions that are more specific:
Making A Switch Adapted Toy by Dave Grass
Here is another way for the more technically challenged:
Save some time and buy a pre-made battery interruptor from Enabling Devices for $9.95. They also have a nice free tutorial pdf on how to install and use their battery interruptors.
I have used a notching file tool that allows me to notch a hole in the side of the battery door so that the cord can fit through. These can be bought through infogrip for $9.
I have found that the straight-forward toy, as far as having a single action and single switch, is a lot easier to adapt. I bought one toy that had 3 settings and by using the interrupter, I only got one feature and it wasn't that exciting. To get to the main brain of the toy, I had to undo a lot of screws only to find a plastic casing I would have had to break. I would suggest looking for the simplest featured toys you can find for this kind of project.
Here are some pictures and links to some fun Halloween toys that might work I found on a quick search:
Switch adapted toys can make all the difference for kids with orthopedic impairments or low functioning students working on cause and effect. Just make sure that you know what stimulates or scares your students so you are not setting them up for a real scare that you didn't intend on having happen! If you have children that have fun with the ghosts and goblins at Halloween, these adapted toys could be a real treat!
All the best to you!