I have a plan to build a phonocardiogram (PCG) with CM-01B piezoelectric sensors.

I found similar research that used the same sensor, but it seems that there is no need to build any additional circuit to send a proper signal from the sensors to the computer unit.

I intend to acquire data using a Raspberry Pi 4B

I am not quite sure about this.

Is it enough to directly connect the sensors by the modified cable (i.e. that can be connected to USB or SDA pin) to Raspberry Pi for getting a good heart sound signal?

  • \$\begingroup\$ Pico ? raspberrypi.org/documentation/pico/getting-started\ with DC bias ? \$\endgroup\$ Feb 23, 2021 at 1:25
  • \$\begingroup\$ What is "the modified cable"? The microphone has an analog output; you will need an ADC to get the microphone data into digital form (the Raspberry Pi doesn't have an ADC built-in). \$\endgroup\$
    – ocrdu
    Feb 23, 2021 at 1:32
  • \$\begingroup\$ That microphone has a metal housing and will be in contact with the patient. It is unsafe to connect it to a Raspberry Pi or other MCU if they are used with an AC power adapter. Think about a battery powered, wireless design instead. \$\endgroup\$ Feb 23, 2021 at 3:16
  • \$\begingroup\$ Good points by @MarkLeavitt. You may want to consider a low durometer skin safe thin film as a barrier to the patient. Something very soft and maybe about the thickness of an exam glove could provide a high dielectric barrier while not inhibiting the mechanical motion of the sensor. \$\endgroup\$ Feb 23, 2021 at 10:02

1 Answer 1


The Raspberry Pi does not have any analog inputs. You'll need to add an analog to digital converter like the MCP33111 or maybe go with the MCP3008 if you want more inputs. Adafruit has a nice ADS1115 breakout board if you don't want to make one yourself.


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