Here is the circuit that produces five tones. This is a simple toy piano circuit with 555 timer. We can also use this circuit as a Machine gun. Main heart of this circuit is 555 timer IC. The 555 timer is operated in astable multi-vibrator mode. In astable multi-vibrator mode, the circuit produces accurate free running waveforms, which can be adjusted.
Power the circuit and press the first button from right. It produces a tone with high pitch. Now press the second button it’s pitch is slightly lower than the first button. In this way, press all the buttons in order to listen the tones produced by them. This is similar to tones produced by a piano or a machine gun played by children