Indoor noise detection circuit design

In the current era, noise pollution has become a frequent problem in people's daily lives. Under normal circumstances, the sound intensity will be very pleasant when it is below 30dB. If it is higher than 80dB, it will be annoying. If it exceeds 100dB, it will affect people's mental state and cause a series of negative consequences. Increased, severe cases lead to hearing loss, and even cause epilepsy. The noise intensity in the home environment is about 47dB, but the Hi-Fi sound system and the high-volume playback TV may increase the sound intensity to a level that threatens human health. To test the noise intensity in the room, we designed a circuit that detects and displays the noise intensity, and emits a flash warning when it exceeds the specified allowable intensity. As shown in the figure, it is an indoor noise detection circuit.