Arduino UNO Q - Sound Sensor
A sound sensor detects sounds in the environment and outputs a digital signal. It includes an onboard potentiometer to adjust sensitivity. Use it to trigger actions when a clap, knock, or loud noise is detected. With Bridge and Telegram, your Arduino UNO Q can send you instant alerts when it hears a sound.
In this tutorial, you will learn:
- What a sound sensor is and how it works
- How to wire the sound sensor to the Arduino UNO Q MCU
- How to read the digital output to detect sounds
- How to use Bridge to expose sound state and events to the Linux side (Python)
- How to receive Telegram alerts when sound is detected on Arduino UNO Q
- How to use OpenClaw on Arduino UNO Q with the sound sensor
Hardware Preparation
Or you can buy the following kits:
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Additionally, some of these links are for products from our own brand, DIYables .
Additionally, some of these links are for products from our own brand, DIYables .
Overview of the Sound Sensor
A sound sensor module has a small microphone that detects vibrations in the air (sound waves). The module converts these into a digital signal:
- HIGH: Quiet — no sound detected above the threshold
- LOW: Sound detected
The module includes:
- VCC pin: 3.3V to 5V power supply
- GND pin: Ground
- OUT pin: Digital output — HIGH = quiet, LOW = sound detected
- Onboard potentiometer: Adjusts detection sensitivity
- PWR LED: Power indicator
- Sound LED: Lights up when sound is detected
How to Adjust Sensitivity
Turn the potentiometer on the module:
- Clockwise: More sensitive (detects softer sounds)
- Counter-clockwise: Less sensitive (only loud sounds trigger it)
Adjust it until the Sound LED reliably triggers on a clap or knock but stays off in ambient noise.
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
| Sound Sensor Pin | Arduino UNO Q MCU |
|---|---|
| GND | GND |
| VCC | 5V |
| OUT | D8 |
If you plan to keep this circuit, think about screw terminals. You can stack a Proto Screw Terminal Block Shield or a Screw Shield V2 on the Arduino UNO Q and connect the wires to its screw terminals. The diagram below shows the same wiring with the Screw Shield V2.
This image is created using Fritzing. Click to enlarge image
How To Program For Sound Sensor
- Configure the sensor pin as a digital input:
pinMode(SENSOR_PIN, INPUT);
- Read the digital output:
int sound_state = digitalRead(SENSOR_PIN);
- Detect sound events by comparing to the previous state:
if (prev_state == HIGH && sound_state == LOW)
Serial.println("Sound DETECTED");
else if (prev_state == LOW && sound_state == HIGH)
Serial.println("Quiet again");
prev_state = sound_state;
Arduino UNO Q Code
The Arduino UNO Q has two processors working together:
- The STM32 MCU reads the sound sensor's digital output and detects sound events
- The Qualcomm MPU runs Debian Linux with Wi-Fi — in this section, only the MCU is programmed. A later section shows how both processors work together via Bridge.
/*
* This Arduino UNO Q code was developed by newbiely.com
*
* This Arduino UNO Q code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-sound-sensor
*/
// Sound sensor DO pin: HIGH = quiet, LOW = sound detected
// Sensitivity is adjusted by the onboard potentiometer
#define SENSOR_PIN 8 // The Arduino UNO Q MCU pin connected to OUT of the sound sensor
int prev_sound_state = HIGH;
int sound_state;
void setup() {
Serial.begin(9600);
pinMode(SENSOR_PIN, INPUT);
Serial.println("Arduino UNO Q Sound Sensor ready");
}
void loop() {
sound_state = digitalRead(SENSOR_PIN);
if (prev_sound_state == HIGH && sound_state == LOW)
Serial.println("Sound DETECTED");
else if (prev_sound_state == LOW && sound_state == HIGH)
Serial.println("Sound gone — quiet again");
prev_sound_state = sound_state;
}
Detailed Instructions
First time with Arduino UNO Q? Follow the Getting Started with Arduino UNO Q tutorial before proceeding.
- Connect: Wire the sound sensor to the Arduino UNO Q MCU as shown in the wiring diagram.
- Open Arduino App Lab: Launch Arduino App Lab and wait until it detects your Arduino UNO Q.
- Create a new App: Click the Create New App button.
- Give the App a name, for example: SoundSensor
- Click Create to confirm.
- Paste the sketch: Copy the MCU code above and paste it into sketch/sketch.ino.
- Upload: Click the Run button in Arduino App Lab.
- Clap near the sensor or tap the table — observe the Serial Monitor output.
- Adjust the potentiometer on the module if detection is not reliable.
App Lab Console Output
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:00:01] Arduino UNO Q Sound Sensor ready
[2026-04-29 09:00:05] Sound DETECTED
[2026-04-29 09:00:05] Sound gone — quiet again
[2026-04-29 09:00:08] Sound DETECTED
[2026-04-29 09:00:08] Sound gone — quiet again
Bridge: Linux + MCU
This section shows how to program both processors of the Arduino UNO Q so the Linux side can read sound state and receive sound events via Bridge:
- The sound sensor is connected to the MCU — the MCU monitors the digital output continuously and caches the current state
- The MPU cannot read the sensor pin directly — it calls Bridge functions to get the current state or check for new sound events
- The MPU has Wi-Fi — running full Debian Linux, it can send Telegram alerts the moment a sound is detected
- Arduino_RouterBridge enables RPC communication between the two processors
- ⚠️ /dev/ttyHS1 (Linux) and Serial1 (MCU) are RESERVED by the router — never open them in user code
In short: MCU detects sound via DO pin → sets event flag → MPU polls Bridge → MPU sends Telegram alert.
MCU Code (Bridge)
/*
* This Arduino UNO Q code was developed by newbiely.com
*
* This Arduino UNO Q code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-sound-sensor
*/
#include "Arduino_RouterBridge.h"
#define SENSOR_PIN 8 // The Arduino UNO Q MCU pin connected to OUT of the sound sensor
bool cached_sound = false; // true = sound present
bool sound_event = false; // true = new sound detected (rising edge)
int prev_state = HIGH;
String get_state(String arg) {
return cached_sound ? "sound" : "quiet";
}
String get_event(String arg) {
if (sound_event) {
sound_event = false;
return "sound_detected";
}
return "none";
}
void setup() {
Bridge.begin();
Monitor.begin();
pinMode(SENSOR_PIN, INPUT);
Bridge.provide("get_state", get_state);
Bridge.provide("get_event", get_event);
Monitor.println("Arduino UNO Q Sound Sensor Bridge ready");
}
void loop() {
int current = digitalRead(SENSOR_PIN);
if (prev_state == HIGH && current == LOW) {
// Quiet → Sound
cached_sound = true;
sound_event = true;
Monitor.println("Sound detected!");
} else if (prev_state == LOW && current == HIGH) {
// Sound → Quiet
cached_sound = false;
Monitor.println("Quiet again.");
}
prev_state = current;
}
Python Code (Bridge)
"""
This Arduino UNO Q script was developed by newbiely.com
This Arduino UNO Q script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-sound-sensor
"""
from arduino.app_utils import *
import time
def loop():
state = Bridge.call("get_state")
print(f"Sound state: {state}")
time.sleep(0.5)
App.run(user_loop=loop)
Detailed Instructions
- Connect: Wire the sound sensor to the Arduino UNO Q as shown in the wiring diagram.
- Open Arduino App Lab and create a new App named SoundSensorBridge.
- Paste the MCU sketch into sketch/sketch.ino.
- Paste the Python code into the Python file.
- Install the library: Click the Add sketch library button (the open book icon with a + sign) in the left sidebar.
- Search for Arduino_RouterBridge created by Arduino and click the Install button.
Bricks
No bricks added...
Sketch Libraries
No sketch libra...
Files
python
sketch
.gitignore
README.md
app.yaml
sketch.ino
- Upload: Click the Run button.
- Clap near the sensor — observe the event appear in both consoles.
App Lab Console Output
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:00:01] Arduino UNO Q Sound Sensor Bridge ready
[2026-04-29 09:00:05] Sound detected!
[2026-04-29 09:00:05] Quiet again.
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:00:02] Sound state: quiet
[2026-04-29 09:00:03] Sound state: quiet
[2026-04-29 09:00:05] Sound state: sound
[2026-04-29 09:00:06] Sound state: quiet
Telegram
Receive instant Telegram alerts when sound is detected on the Arduino UNO Q sound sensor.
MCU sketch: Keep the same MCU sketch from the previous Bridge section.
Python Code (Telegram)
"""
This Arduino UNO Q script was developed by newbiely.com
This Arduino UNO Q script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-sound-sensor
"""
from arduino.app_utils import *
import requests
import time
TELEGRAM_BOT_TOKEN = "YOUR_TELEGRAM_BOT_TOKEN"
CHAT_ID = "YOUR_CHAT_ID"
last_update_id = 0
def get_updates():
global last_update_id
url = f"https://api.telegram.org/bot{TELEGRAM_BOT_TOKEN}/getUpdates"
params = {"offset": last_update_id + 1, "timeout": 5}
try:
response = requests.get(url, params=params, timeout=10)
data = response.json()
if data["ok"]:
return data["result"]
except Exception as e:
print(f"Error getting updates: {e}")
return []
def send_message(chat_id, text):
url = f"https://api.telegram.org/bot{TELEGRAM_BOT_TOKEN}/sendMessage"
payload = {"chat_id": chat_id, "text": text}
try:
requests.post(url, data=payload, timeout=10)
except Exception as e:
print(f"Error sending message: {e}")
def loop():
# Auto-alert on new sound detection
global last_update_id
event = Bridge.call("get_event")
if event == "sound_detected":
print("Sound detected! Sending Telegram alert.")
send_message(CHAT_ID, "🔊 Sound detected by Arduino UNO Q!")
# Handle Telegram commands
updates = get_updates()
for update in updates:
last_update_id = update["update_id"]
if "message" not in update:
continue
message = update["message"]
chat_id = message["chat"]["id"]
text = message.get("text", "").strip()
print(f"Received: {text}")
if text == "/start":
send_message(chat_id,
"Arduino UNO Q Sound Sensor Bot\n"
"/state - Current sound state (sound / quiet)\n"
"Automatic alert when sound is detected")
elif text == "/state":
result = Bridge.call("get_state")
send_message(chat_id, f"Sound state: {result}")
else:
send_message(chat_id, "Unknown command. Send /start for help.")
time.sleep(0.3)
App.run(user_loop=loop)
Detailed Instructions
- Replace YOUR_TELEGRAM_BOT_TOKEN with your actual bot token from BotFather.
- Replace YOUR_CHAT_ID with your Telegram chat ID.
- Paste this Python code into your App's Python file (keep the same MCU sketch).
- Click the Run button — clap near the sensor to trigger a Telegram alert.
App Lab Console Output
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:10:00] Waiting for Telegram messages...
[2026-04-29 09:10:05] Sound detected! Sending Telegram alert.
[2026-04-29 09:10:10] Received: /state
Telegram
12:45
Welcome to Telegram!
ArduinoBot
10:19
Chatting with Arduino...
BotFather
Yesterday
Your bot has been created.
ArduinoBot
bot
OpenClaw
You can adapt the OpenClaw to this tutorial by refering the instruction on Arduino Uno Q - OpenClaw Tutorial
Project Ideas
You can build many useful projects with the sound sensor and Arduino UNO Q:
- Clap Switch: Detect two quick claps and toggle a relay via Bridge to turn a light or fan on or off — Python counts clap events within a 500 ms window and sends the toggle command
- Baby Monitor: Mount the sensor in a room — when it detects continuous sound (crying), the MPU sends a Telegram alert so you know immediately from anywhere in the house
- Intrusion Alert: Combine the sound sensor with the door sensor — Telegram alerts for both door open and unexpected loud noise, with timestamp and duration logged to a file on Linux
- Sound Level Logger: Poll the sound state every second and log detection frequency to a CSV — send a daily Telegram report showing peak sound hours for noise monitoring
- Smart Doorbell: Detect a knock on the door via sound sensor — the MPU sends a Telegram message with a photo (if a camera is attached) so you can see who's at the door remotely
Challenge Yourself
Ready to go further with the sound sensor on Arduino UNO Q? Try these challenges:
- Easy: Add a sound counter to the Python code — count how many times sound is detected per minute and print the total every 60 seconds in the console.
- Medium: Implement clap pattern recognition in Python: detect a double-clap (two sounds within 600 ms) versus a single clap — send different Telegram messages for each pattern.
- Advanced: Build a sound duration tracker: record the start and end time of each sound event on the MCU side using millis() — expose the last duration via a get_duration() Bridge function and include it in every Telegram alert.