by Victoria Nguyen
What is it?
This sensor emits a signal if the microphone of the sensor detects a noise. The sensitivity of the sensor can be adjusted by means of a controller.
The KY-038 sound sensor module consists of capacitance sensitive microphone (50Hz-10kHz) and an amplification circuit. The module converts sound waves to electrical signals.
It detects the sound with the help of a microphone and then feeds this sound to processing circuitry which consists of an operational amplifier LM393. It also consists of a potentiometer which is used for setting the sound level and by setting this sound level the output of this sound sensor module could be easily controlled.
Output
This sensor is ideally suited for threshold measurement. This means that the sensor emits a digital high signal as soon as a threshold value set by the user is exceeded. However, this also means that the analog measured values are not suitable for conversions, as the analog signal is also influenced by the rotary potentiometer.
Digital output: Via the potentiometer, a limit value for the received sound can be set, at which the digital output should switch; the output high and low signal
Analog output: Direct microphone signal as voltage level
LED1 : Shows that the sensor is powered
LED2 : Indicates that a noise has been detected
Pins
The sound sensor module consists of four pins Ao, Vcc, GND, and Do. Ao pin is used of analog output, Vcc pin is used for giving supply voltage to this sound sensor module which is 5V dc. Similarly, a GND pin is used for giving ground to this sound sensor module, and a D0 pin is used for digital output.
Components
This sensor has three functional components on its circuit board:
- Front sensor: physically measures the environment and outputs it as an analog signal to the second unit
- Amplifier: amplifies the signal depending on the resistance set on the rotary potentiometer and sends it to the analog output of the module
- Comparator: switches the digital output and the LED when the signal falls below a certain value. This value (and thus the sensitivity of the module) can be adjusted via the rotary potentiometer
Potentiometer
Here it is to be noted: The signal is inverted. If a high value is measured, this results in a lower voltage value at the analog output.
The potentiometer is used to adjust the sensitivity of the digital output pin. When a particular sound will be higher/lower than the threshold level, the digital output will be low/high. In our case, the digital output will be HIGH and it will be LOW when the sound will be detected.
You will have to calibrate the sound sensor in order for it to detect the sound precisely. The potentiometer will help us calibrate the sensor. Rotate the potentiometer anti-clockwise to increase the sensitivity of the sensor and rotate it clockwise to decrease its sensitivity.
Schematics
Code and Serial Monitor
Resources
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