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Selecting MEMS microphone for cardiac auscultation

#1

Respected All,

I want to choose specific MEMS microphone to make an electronic stethoscope.

Will the below MEMS microphone serve the purpose of detecting low frequency heart sounds with high signal to noise ratio ?

Digi-Key Part Number 1528-1908-ND
Description SPH0645LM4H I2S MICROPHONE BOARD

[adafruit_i2s_digital_mems_microphone_breakout-1396529.pdf|attachment]
(upload://cZAEWazMRlZ5fjECypmLkiqPJ33.pdf) (3.8 MB) Product details

Also kindly suggest suitable specific model of microcontroller (Arduino or Rasberry Pi) to get Heart sounds in .wav format for further signal processing

Thanking You,

Yours Sincerely,
Ajiket Patil

#2

Greetings,

Much will depend on the design of the mechanical system used to link the microphone to the signal source; this is probably as important or more so than the selection of components used.

Please note that part number 1528-1908-ND is a 3rd party evaluation board for the Knowles Acoustics microphone P/N SPH0645LM4H. While it may be useful as a development aid, use of the 1528-1908-ND for production purposes is not recommended.

In terms of microphone selection, the IM69D130V01XTSA1 may be another device worth considering, due to its improved sensitivity at low frequencies.

With the exception of some of the smallest/lowest powered examples, most modern microcontrollers would be capable of capturing information from such a device and saving it to some sort of external memory device. Please note that neither Arduino nor Raspberry Pi devices are microcontrollers per-se; they are hardware modules that combine a microcontroller with support and accessory components in a standardized fashion, allowing users to avoid low-level hardware design and more easily share/reuse software.

That said, the lower power consumption of the Arduino platforms relative to the Pi would probably make it a better choice for an application such as this.

1 Like
#3

Respected rick_1976 Sir,
Greetings !
Thank You very much for your reply.

Following are the components I am planning to purchase

  1. ARDUINO MKR WIFI 1010 Digi-Key Part Number ‎1050-1162-ND‎
    ( For Wifi and Bluetooth connectivity)
  2. EVAL KIT IM69D130 20-FLEX 4-ADAP Digi-Key Part Number EVALIM69D130FLEXKITTOBO1-ND‎ (As per your suggestion)
  3. SPH0645LM4H I2S MICROPHONE BOARD ‎Digi-Key Part Number 1528-1908-ND‎ ( As I2S output is better immune to noise)
    cart
    cart1362×575 92.3 KB

I will have input to the microphones from the headsets of a conventional acoustic stethoscope.

You are requested to give your valuable suggestions for the project.

#4

Respected rick_1976,
Greetings!
Sir, Awaiting for your reply on the selection of the above components. The above components are not available directly in India, thus i want be sure on their selection.

I have already purchased a conventional acoustic stethoscope.

Thanking You,
Ajiket

#5

Those look like reasonable choices to me. I would point out though that a single microphone is probably all that’s needed for the application.

1 Like
#6

Respected rick_1976,

Sir, I am taking board for ease of connections sir (The size of individual microphones is small)

Thank You very much for your response.