Simple doorbell Using UM66

Below is a simple circuit of doorbell using UM66. The circuit can be assembled in a general purpose PCB and enclosed in any toys. 

Parts

C1 - 220 µF 10v
VR1 - 100 k pot
VR2 - 10 k pot
T1 and T2 - BC548
IC1 - UM66

Speaker - 8 ohms
Power - 3v