Snoring is a sleep behavior that probably many have experienced or at least witnessed. It can occur due to various reasons including deceases, exhaust, sleep position, age, excess weight, anatomical features. Anyway the aim of following project was only to detect snoring and record it’s events to SD card.
Project is built around AVR microcontroller which reads sound from microphone amplifier and filter using ADC channel. Sound was filtered with 2kHz Butterworth filter because biggest snore intensity is low fre q. Then ADC sampling was set at 8kHz. In continuous recording mode snore readings are pushed directly to SD card as a CSV file. This data can be analyzed later on PC software like Matlab or Octave. More interesting is trigger mode which incorporates basic DSP routine. In trigger mode data is logged only when snoring is detected. First of all sound is compared to preset threshold level then passed though 3s window where at least two snore spikes are expected.