The Bowser Home Security System

I'm brand new to trying to build things, but am handy at soldering and willing to learn. I have an idea for a home security system that makes someone think there's a big dog right next to the door.

I'm thinking that it could be triggered by a wireless doorbell or possibly a sensor that could detect knocking. I'd want a toggle option so that it's a regular doorbell or deactivated when I'm at home.

In order to create the effect of a dog, I want one speaker to be mounted high and a second low. The low one will play sniffing noises and the top one will trigger the doorbell and menancing dog sounds. If I can also run it so that solenoids could trigger the sound of a big dog jumping at the door, it would be bonus realism.

Before setting off on trying to create it, I was hoping to get advice on what hardware I would need to create it and some good resources for learning how to make something like this even if it's rough around the edges.

You can get an [u]MP3 Shield[/u]* for the Arduino. The Arduino simply triggers the sound... The MP3 board has the memory for the music, a DAC, a clock, and the MP3 decoder, etc.

You can also get [u]Microphone Breakout Board[/u] that has a microphone, preamp, and the appropriate biasing built-in. (The audio signal has to be biased/offset because the Arduino can't read negative voltages so it can't handle the negative half of the AC audio signal.

Then you'll need an amplifier and speaker. For realistic sound, I'd guess you're going to need at least 20 Watts and a good speaker with at least an 8-Inch woofer.

In order to create the effect of a dog, I want one speaker to be mounted high and a second low. The low one will play sniffing noises and the top one will trigger the doorbell and menancing dog sounds.

The location probably isn't that critical. It's hard to locate the sound-direction when listening through a door. It's more important to get a loud and realistic sound.

If I can also run it so that solenoids could trigger the sound of a big dog jumping at the door, it would be bonus realism.

You can drive a solenoid from the Arduino with an additional transistor or MOSFET driver circuit. I'll leave that for you to work on later...

...Time for a story -
A burglar is breaking onto a house.

He hears a voice say, "I see you and The Saint sees you". He freezes for a moment until he realizes that the voice sounds fake.

He continues and steps-in through the window, and again, "I see you and The Saint sees you".

He finds the light switch, switches it on, and sees a parrot. He's relieved and he says, "Stupid parrot."

The parrot says, "Sic-em, Saint!"

Of course you need a “woofer” for dog sounds :slight_smile:

This looks promising, any recommendations for something that could be triggered by knocking on a door? It seems more believable then just pushing a doorbell. As far as power goes, will a standard switching power supply be the beat route or are there boards I can get that are more compact? Finally, anything I should think about in terms of the on off switch? Once I get a rough draft, I might want to set it up to text me when it goes off. Any other functions that you can recommend to add to its usability is very much appreciated