Grove - Loudness Sensor


3.3V 5.0V Analog

The Grove - Loudness Sensor is designed to detect the sound of environment. Based on LM2904 amplifier and a built-in microphone, it amplifies and filters the high frequency signal that received from the microphone, and outputs a positive envelop. This is used for Arduino’s signal acquisition. The output value depends on the level of sound input. In order to avoid unnecessary signal disturbances, input signal will go through two times’ filtering inside the module. There is a screw potentiometer that enables manual adjustments to the output gain.


  • Voltage :3.5~10 VDC
  • Working Frequency :50~2000 Hz
  • Sensitivity : -48~66 dB
  • Signal-to-noise Ratio : >58 dB
  • Output Signal range : Analog Signal (0-1023)


More details about Grove modules please refer to Grove System

Platforms Supported

Getting Started

With Arduino


This module uses the chip LM2904 to amplify the electronic signal produced by the mini microphone. At last, you’ll get the analog-to-digital conversion value. Let’s try to read the output value.

Here we will show you how this Grove - Loudness Sensor works via a simple demo. First of all, you need to prepare the below stuffs:

Seeeduino V4 Grove - Loudness Sensor Base Shield
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  • As the picture on the below indicates, the Loudness sensor is connected to analog port A0 of the Grove - Base Shield.

  • Connect Arduino/Seeeduino to PC by using a USB cable.


  • Copy and paste code below to a new Arduino sketch.
int val;
void setup()

void loop()
    val = analogRead(0);
  • Upload the code.
  • Then open the serial monitor to observe the output results. There will be a significant change when blow to the sensor.

Here is the test screenshot from the oscilloscope. The blue line is the original signal from microphone and the yellow is the sig pin of Loudness Sensor. It is the original signal envelope that the module outputs.

Blowing to the sensor:

Speaking to the sensor:

With Raspberry Pi


  • First, You need to prepare the below stuffs:
Raspberry pi Grove - DHT Sensor pro Grovepi+
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  • Follow instruction to configure the development environment.

  • Plug the sensor to grovepi socket A0 by using a grove cable.


  • Navigate to the demos’ directory:
    cd yourpath/GrovePi/Software/Python/
  • To see the code
    nano   # "Ctrl+x" to exit #
    import time
    import grovepi

    # Connect the Grove Loudness Sensor to analog port A0
    loudness_sensor = 0

    while True:
            # Read the sound level
            sensor_value = grovepi.analogRead(loudness_sensor)

            print "sensor_value =", sensor_value

        except IOError:
            print "Error"
  • Run the demo.
    sudo python


ArduinoWioBeagleBoneRaspberry PiLinkIt ONE


The platforms mentioned above as supported is/are an indication of the module's hardware or theoritical compatibility. We only provide software library or code examples for Arduino platform in most cases. It is not possible to provide software library / demo code for all possible MCU platforms. Hence, users have to write their own software library.

Help us make it better

Thank you for choosing Seeed. A couple of months ago we initiated a project to improve our documentation system. What you are looking at now is the first edition of the new documentation system. Comparing to the old one, here is the progresses that we made:

  • Replaced the old documentation system with a new one that was developed from Mkdocs, a more widely used and cooler tool to develop documentation system.
  • Integrated the documentation system with our official website, now you can go to Bazaar and other section like Forum and Community more conveniently.
  • Reviewed and rewrote documents for hundreds of products for the system’s first edition, and will continue migrate documents from old wiki to the new one.

An easy-to-use instruction is as important as the product itself. We are expecting this new system will improve your experience when using Seeed’s products. However since this is the first edition, there are still many things need to improve, if you have any suggestions or findings, you are most welcome to submit the amended version as our contributor or give us suggestions in the survey below, Please don’t forget to leave your email address so that we can reply.

Happy hacking