Simple Musical Calling bell

This is a simple musical calling bell. You can make it with a little budge, about 50 tk only.
Lets see the circuit

Required parts :
1. 3 pin IC UM66T                                       10-15 tk
2. Pencil Battery Casing                               25 tk
     You can use any other case or broken toy's battery holder which will reduce your cost.
3. 4-5 fit wire                                                  10 tk
4. A small 8(ohm) speaker                            20 tk
        You can use any other speaker taken form Walkman or toys.
 5. 1 bed switch                                              10-15 tk

Working Procedure:
1. Connect the circuit element according to the diagram.
2. If you want to use a long wire then use the switch between speaker and pin no 1.