When I created this video, I didn't have the intention of making an instructable, but I figured why not. The schematic is talked about at the very end of the video. It is very easy to put together. You don't need to use the same parts that I did in the video. There are other emergency buttons and sirens out there, and perhaps even as close as your local electronics store. While I do sell the parts in the video, you can just as easily take a stroll around town, and if you're lucky you may be able to find the parts required to build this in an afternoon.
The premise is this: Someone breaks into your home in the middle of the night. You have one of these in your room. Press the panic button, and the whole neighbourhood will hear it. If you have the siren facing a window, they may even see the flashing LEDs.
In the time it takes for an intruder to find this module, it will be too late. The damage has been done. Ideally, it would act to scare intruders away. You can hide it in an optimal place so that they can't easily rip out the power supply. As well, you can add a battery backup with ease so that if one supply is disconnected, they have to search for the alternate supply to disengage. You can be really creative with how you set this bad boy up.
The emergency button requires a key in order to disengage. Depending on the quality of your emergency switch, the lock can be picked, but it would take the intruder time to find it and pick up. That would take at least a few minutes. The siren in this video is extremely loud, but there are louder ones out there that are just as compatible. Many sirens work off of 12v, and other common ones work on 3v. At least the ones I've commonly seen.
Anyhow, I hope you enjoy the video, and perhaps it will inspire you to create your own. You can take this idea, and build on it very easily. Thanks for watching, and have a wonderful day =)