You don't need much to make this little gadget.
- A buzzer
- An attiny13
- An IR - receiver
- A small battery (3V)
- A soldering iron and solder
- A bit of wire or a batteryclip to connect the battery
You might ask why I used these parts and there is only one reason: I had them in my parts-box!
The IR-receiver didn't have an id-number on it but a PNA4601M should do the trick.
I used the attiny13 because it runs on very low voltages (2.7V-5.5V ant the attiny13V even starts from 1.8V)so it runs from a tiny 3V battery and ofcourse the small size is a plus in this project.
If you don't know how to program an atmel microcontroller, I should suggest you to browse around in the Instructables here. There are very good Instructables about making programmers and how to program.Please be careful when soldering. Children should always work under adult supervision!