Remotely controlled beeping device

[technoyos]

Hello,
I'm a real Noob to this electronics thing (but I find it fascinating..). Anyway, I want to try to build a device that beeps. The duration and pitch of the beep is fixed, but the frequency should be variable, depending on user input. The whole device should be as small as possible and water proof.
I would prefer to be able to control the beep frequency remotely - perhaps from a mobile phone or from something like a remote controller. The beeping unit should be kept simple as possible.
Any ideas or suggestions on how I can achieve this?

Thanks,
Yossi

 

[ALERTLINKS]

tone = pitch = frequency.
Do you mean repetition rate?

See this project,You can control it using tv remote
http://electroschematics.com/6249/remote-controlled-alarm/

Or this, it responds to whistle.
http://www.diy-electronic-projects.com/p109-Whistle-Responder.

Or make this circuit to get a start,
http://electroschematics.com/6009/warning-alarm-with-cd4001/