Portable digital stethoscope with record and playback
Stethoscopes are intensively used by physicians. Some of them are modern other are old fashioned. But in many cases technology may help to see what human may skip/not notice. This is why computer aided diagnosis (CAD) is important. Having this in mind Cornel ECE4760 students Michael Wu and Garen Der-Khachadourian constructed a digital stethoscope with many useful features that may be helpful when analyzing cardiac signals.
Digital stethoscope is based on AVR Atmega644 microcontroller which captures sound signal using sensor and digitizes at 8kHz. All captured signals are passed to audio output using PWM for real time auscultation. Additionally signal waveform is recorded in to 1MB external flash memory chip so later waveform could be played back. User interactions are seen in 4×20 LCD and controlled with 16 button keypad. Besides that digital stethoscope sends real time (or recorded) waveform data via USART where Matlab program analyzes it and calculates other derivative information like average hear-beat rate. Having visual information such system may help to detect cardiac murmur that can be unnoticed during standard checkups.




