Agreeable, very close sound imitation
Suitable for sound effects, door-bells etc. 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.
IC1 is wired as a square wave generator and produces both tones