This is knock the melody. It uses begin flasher circuit in building sound click keen go up at a loudspeaker. But each time at PNP-transistor, Q2 type(2N3906-2N2907-or-BC558) work by origin frequency circuit that use RC and Q1-NPN transistor-type(2N3904 or 2N2222-or BC549) ,R2-potentiometer–50K is used for fine working rate repeatedly through 20-280 sections time per minute(tone), By value change of C1 (0.1uF to 22uF) will change the tone of voice in the sound click at happens