TONE GENERATOR AND SPEAKER The tone generator and speaker module emits the appropriate sound determined by the PIC microcontroller. There are four distinct alarms [7]. The temperature detector alarm and smoke alarm both sound at 4 kHz; however the
temperature alarm is sounded at a higher volume level. In addition, there is a detected signal alarm (smoke or fire detected at another detector) that sounds at 2 kHz. There is also a low battery alarm that sounds at 500 Hz