Our proposed device, the Stethoscope Amplification System (S.A.S), accurately amplifies and broadcasts auscultation sound of mammalian patients within an ergonomic handheld device. Our device solution consists of a 3D printed case in an ergonomic L-shape that holds our PCB board, traditional stethoscope head, and all additional components to make the device function. This includes an on/off button as well as an LED indicator, volume adjustment wheel, microUSB charging port and lanyard keyhole. Our design also consists of a coupler that serves as the connection from the speaker head to the microphone on the PCB for our device. 

 

The 3D printed case is made of Onyx for the purpose of durability and maintaining low mass. The case is designed with a snap fit structure for locking the two separate 3D printed pieces together while allowing for insertion of all the electronic components. The device is securely attached with a lanyard attachment to ensure portability of the device and increase comfort from carrying a traditional stethoscope. The L-shape design of our device allows the veterinarian to hold the device in a comfortable position that optimizes the amount of contact of the stethoscope head to the patient. It also ensures an easy hold for veterinarians' hands of left or right, large or small.

 

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The electronics that were incorporated to make our device function included the PCB amplification and filtering circuits, microphone, speakers, and battery. The amplification circuit placed on our PCB receives the signal from the microphone and sends it to the preamplifier, which goes through a bandpass filter and finally a LM386 amplification IC where it is sent to our two speakers as output. 

Unlike other digital stethoscopes in the market, our device is inexpensive and falls within the market range that students and veterinarians inputted in our preliminary surveys. Its one-step process allows for veterinarians to quickly examine their animals without having to constantly put on and remove their headphones, as with the Littmann series, and allows for large group demonstrations to have an easier way to understand auscultations. Since our device follows the same method of handling as the regularly used Littmann Classic, it will make it easier for veterinarians to understand and use the S.A.S making it more widely adopted in the educational and work fields.