Microphone Sound Detector Module

Outputs analog and digital output when an adjustable threshold reached

DESCRIPTION

The Microphone Sound Detector Module detects sound waves and outputs both an analog version of the sound and a digital output when an adjustable sound threshold is reached.

PACKAGE INCLUDES:

• Microphone Sound Detector Module

KEY FEATURES OF MICROPHONE SOUND DETECTOR MODULE:

• Microphone has frequency range of 50 Hz – 13 kHz
• Outputs the analog version of the sound
• Outputs a digital logic level based on an adjustable sound threshold
• LED illuminates when digital sound threshold is reached
• 5V operation

This module incorporates a small microphone and provides 2 different outputs.  One is an analog voltage representation of the sound that the microphone is picking up and the other is a digital output that goes HIGH when the sound goes above a threshold set using a potentiometer.

The analog output sits at approximately 2.5VDC (1/2Vcc) with no input, but this varies with the setting of the adjustment pot.  Any sound picked up by the microphone is imposed as an AC signal riding on this DC bias level.  The signal can be AC coupled using a capacitor to remove the DC bias if desired.

The digital output which is active HIGH, is the result of a LM393 voltage comparator IC comparing the sound amplitude to the level set by the on-board potentiometer.  Turning the pot CW increases the sensitivity.  There is a LED near the pot that comes on when the output goes active HIGH.  If the pot is turned CCW (less sensitive), the LED will always be off and if it is turned fully CW (more sensitive) it will always be on.  For best sensitivity, you will want to adjust the pot CW so that the LED is on and then adjust the pot back CCW just until the LED goes off.  That will give you the most sensitivity.  The pot can be adjusted further CCW to decrease the sensitivity and increase the sound level at which the output goes HIGH..

The board also has a red LED which lights whenever power is applied.

Module Connections

The module has a 4-pin header on the assembly for making connections.

1 x 4 Header 

• A0 = Analog output, connects to analog input on uC
• G or GND  = Ground
• ‘+’ = 5V
• D0 = Digital output, connects to digital input on uC

OUR EVALUATION RESULTS:

This is a useful module for experimenting with sound or taking an action based on detecting a sound of some magnitude.  For instance the digital output

Sensitivity of the microphone is pretty good.  We measured a frequency range of about 50Hz to 13KHz.  The scope capture below shows the analog output when the microphone picked up a 1 kHz whistle.  This waveform rides on a 2.5V DC level, so the signal was AC coupled for display.  Amplitude depends on the sound volume, in this case it was about 40mV.

BEFORE THEY ARE SHIPPED, THESE MODULES ARE:

• Sample inspected and tested per incoming shipment.

Notes: 

1. The microphone module may be mounted flush to the board rather than at right angle as shown in the pics.

TECHNICAL SPECIFICATIONS