To make the effect even better you can add sound effects. To do this you need a simple sound player. I am just using a cheap sound recorder module that I got from Radio Shack.
Before connecting the player, you need to see how the play button is wired up. In most cases one side of the button will be wired to ground. The other side of the button will be wired to the play pin on the IC chip and to a pull-up resistor. If this is the case, all you need to do is connect the ground of both circuits and connect the play pin to the switch.
The easiest way to connect the ground lines of both circuits is to connect the negative terminals of both batteries with a small piece of wire.
To connect to the play pin on the module, look for any open pin holes on the circuit board that are connected to that side of the switch. If there are no available pin holes, you will need to solder to the surface of the button connectors. After connecting a wire to the board, you need to connect the other end of the wire to the switch terminal that is not connected to the battery.
Here is how that all worked with my setup. On the battery pack of the lights, there are two wires connected to the spring on the negative end. One goes to the switch and the other goes to the play pin on the recording module. On the opposite side of the separator card, two wires are connected to the negative terminal of the light’s battery. One wire goes to the switch and the other wire goes to the negative terminal of the sound recorder’s battery.
Whenever the box is opened, the lights will come one and the pre-recorded sound will play. You can make up your own sound effects or you can find a lot online. Just play them on your computer, and hold the recorder up to your speakers.