How to Build a Small DC Power Loss Beeper Circuit Without External Battery?

I'm new to electronics, but capable of soldering and following directions and schematics. I have an idea for a device and since I don't have the funding to hire an engineer to build a prototype I will try to build it myself, with lots of help from willing experts.

This may already exist, and if it does, makes things easier for me. I need a very small device that will beep if dc power is lost. The device needs to work without external or battery power, but power stored from the source. If source power is lost, the device would give out a few beeps and then stop.

Can someone help me with this?

Hey Abdul,

A few questions.

Is cost an issue?
What is considered "very small"

I have a few solutions in mind but need to know these things.

Thanks,
Matt

Matt,

Yes, it's a cost issue at the moment for me.

The final product needs to be 1/2 " x 1" or smaller, but the prototype can be a larger.

Thanks,
Abdul