This simple project can be used to generate sound which can be heard through a speaker or a buzzer by connecting either of them to its output. The idea is to [[wysiwyg_imageupload::]]generate a frequency in the audible range from a normal pulse generator. Using the circuit in a battery saving mode so that it can work for a longer duration is made possible by using a 555 IC. This IC is known to work in three different modes: bistable, astable and monostable, and can work efficiently in all three modes. Also, being casted in an integrated circuit format makes 555 a power efficient and it can be stretched to work for a longer duration. Read more to find out how the circuit is constructed and how it works.