This circuit generates a two-tone effect very much alike the cuckoo song. It can be used for door-bells or other purposes thanks to a built-in audio amplifier and loudspeaker. Used as a sound effect generator it can be connected to external amplifiers, tape recorders etc. In this case, the built-in audio amplifier and loudspeaker may be omitted and the output taken across C8 and ground. There are two options: free running, when SW1 is left open, and one-shot, when SW1 is closed. In this case a two-tone cuckoo song will be generated at each P1 pressing. Cuckoo Sound Generator Circuit diagram: Parts: R1,R5___________1K 1/4W Resistors R2_____________50K 1/2W Trimmer Cermet R3______________8K2 1/4W Resistor R4_____________82K 1/4W Resistor R6______________1M 1/4W Resistor R7,R17,R20,R21_22K 1/4W Resistors R8,R10,R11,R19_10K 1/4W Resistors R9____________150K 1/4W Resistor R12_____________4K7 1/4W Resistor R13___________100K 1/4W Resistor R14___________220R 1/4W Resistor R15,R22________20K 1...