FC-04 Sound Sensor Module for Arduino with Adjustable Threshold

Description

Here is a complete description of the FC-04 Sound Sensor Module, followed by a usage guide with Arduino, practical examples and programming code.

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🔊 FC-04 Sound Sensor Module – Complete Description

📦 Main Features:

• Name: FC-04 Sound Sensor
• Sensor Type: Analog Microphone + Digital Comparator
• Outputs:
  • Digital (D0): High or low depending on the set threshold
  • Analog (A0): Voltage level proportional to the sound intensity (not always available on all versions of the module)
• Operating Voltage: 3.3V – 5V DC
• Sensitivity Adjustment: Trimmer (potentiometer) to adjust the signal threshold
• LED Indicator: Lights up when the sound level exceeds the set threshold

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🧰 FC-04 Module Components

• Electret Microphone: Detects sound vibrations
• LM393: Voltage comparator to process the microphone signal
• Potentiometer: Adjusts the comparator threshold (sensitivity)
• Output Pin:
  • VCC: Power supply (+3.3V or +5V)
  • GND: Ground
  • D0: Digital output (HIGH/LOW)
  • (some versions also have A0 for analog output)

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🧪 Function

The detector senses ambient sounds through the microphone. The LM393 comparator compares the microphone signal with a threshold (regulated by the trimmer):

• If the sound is below the threshold: D0 = HIGH
• If the sound is above the threshold: D0 = LOW
  (Note: it may vary slightly from module to module, testing is recommended)

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🔌 Connection with Arduino

🔧 Standard connections:

FC-04 Pin	Arduino Pin
VCC	5V
GND	GND
D0	D2 (or another digital pin)

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💡 Example 1: Turn on an LED when there is sound

✅ Objective:

Turn on an LED if a loud noise (clapping, loud voice, etc.) is detected

🔩 Schematic:

• LED with 220Ω resistor on pin D13
• FC-04 on D2

🔁 Arduino Code:

const int soundPin = 2; // Pin collegato a D0 del sensore
const int ledPin = 13; // LED integrato

void setup() {
 pinMode(soundPin, INPUT);
 pinMode(ledPin, OUTPUT);
 Serial.begin(9600);
}

void loop() {
 int soundState = digitalRead(soundPin);
 
 if (soundState == LOW) { // Suono rilevato
 digitalWrite(ledPin, HIGH);
 Serial.println("💥 Suono rilevato!");
 delay(200); // debounce
 } else {
 digitalWrite(ledPin, LOW);
 }
}

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💡 Example 2: Count hand claps

✅ Objective:

Count how many times hands are clapped

🔁 Code:

const int soundPin = 2;
int clapCount = 0;

void setup() {
 pinMode(soundPin, INPUT);
 Serial.begin(9600);
}

void loop() {
 if (digitalRead(soundPin) == LOW) {
 clapCount++;
 Serial.print("Battiti rilevati: ");
 Serial.println(clapCount);
 delay(300); // Antirimbalzo per evitare conteggi doppi
 }
}

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🛠️ Tips for adjustment

• Too many false positives? Turn the potentiometer clockwise to lower the sensitivity.
• Not detecting anything? Rotate counterclockwise to increase sensitivity.
• Use a precision screwdriver for fine tuning.

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📘 Advanced notes: analog output usage (if available)

Some FC-04 modules include a pin A0 for the analog signal. In this case you can obtain the audio waveform or measure the sound intensity in real time.

Example analog code:

const int analogPin = A0;

void setup() {
 Serial.begin(9600);
}

void loop() {
 int value = analogRead(analogPin);
 Serial.println(value);
 delay(100);
}

You can view the graph in Serial Monitor > Serial Plotter.

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📦 Common applications

• Hand clap detection to activate lights or devices
• Sound-based alarm (door slam, voice alarm)
• Interactive games or projects with sound input
• Home Automation and Sound Automations

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📚 Conclusions

The Sound Sensor FC-04 is an economical and simple solution for detecting sounds in Arduino projects. Although it is not suitable for recording or detailed audio analysis, it is perfect for sound events binary (presence/absence of sound). Thanks to the integrated trimmer, it is easy to adapt it to different environments and sensitivities.

If you are interested, I can also provide you with:

• Fritzing Diagrams
• Code for interaction with WiFi modules (e.g., ESP8266)
• Applications with relays or motors

Let me know!

GENERAL	MODEL	Sound Sensor Module
MATERIALS	pcb + components
COMPATIBILITY	ARDUINO
ELECTRONIC COMPONENTS	INPUT VOLTAGE	3 – 15 V
WEIGHT AND DIMENSIONS	PRODUCT WEIGHT	7 g
PACKAGE WEIGHT	0.13 kg
PRODUCT DIMENSIONS (L x W x H)	4.8 x 2 x 0.3 cm
PACKAGE DIMENSIONS (L x W x H)	15 x 10 x 2 cm
PACKAGE CONTENT	PACKAGE CONTENT	1 x Module

We have available the technical sheet of all components, should it not be present in the product download card, send us a message from the contact form and we will publish it as soon as possible on our website.

Tutorial: How to Use FC-04 Sound Sensor

The FC-04 sound sensor is a useful module for anyone who wants to monitor or detect noise in domestic or industrial environments. Ideal for security or automation projects.

What you need

• Arduino
• USB cable
• 5V power supply

Steps

1. Connect the FC-04 module to the Arduino using a jumper cable.
2. Connect VCC and GND to the Arduino power reference (5V and GND).
3. Connect the switch SW to a digital pin of the Arduino for threshold configuration.
4. Connect the signal OUT to another digital pin to receive sensor data.
5. Install the necessary libraries if required by the sketch.
6. Upload the sketch to the Arduino via USB.
7. Check that the module is functioning by monitoring the output port through Serial Monitor.

Example code

void setup() {
 pinMode(OUT_PIN, INPUT);
 pinMode(SW_PIN, OUTPUT);
}

void loop() {
 int soundLevel = digitalRead(OUT_PIN);
 if (soundLevel == HIGH) {
 Serial.println("Rilevato rumore");
 }
}

Mini project

Create a home alarm system that sends an email notification when noise above the set threshold is detected.

Common mistakes

• Fail to properly verify the module’s power supply.
• Set the threshold too low or too high.
• Ignore the calibration data required for the sensor.
• Do not use an inadequate antenna if you intend to use the module in outdoor environments.

Recommended accessories

• ESP8266 Wi-Fi Module
• Buzzer
• 16×2 LCD Display
• Relay Module

Frequently asked questions

How do I set the sensor threshold?
Use a digital pin to enable or disable the threshold setting; check the specifications in the datasheet.

The module does not work with 3.3V power supply.
Check that the sensor is designed to work at 3.3V; otherwise, use a logic level converter.