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) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
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 |
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
*/
// COPYRIGHT newbiely.com
// AUTHOR: newbiely
// This code is made available for public use without restriction.
// For complete instructions, tutorials, and further information, 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
*/
// COPYRIGHT newbiely.com
// AUTHOR: newbiely
// This code is made available for public use without restriction.
// For complete instructions, tutorials, and further information, 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 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
*/
# COPYRIGHT newbiely.com
# AUTHOR: newbiely
# This code is made available for public use without restriction.
# For complete instructions, tutorials, and further information, 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 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
*/
# COPYRIGHT newbiely.com
# AUTHOR: newbiely
# This code is made available for public use without restriction.
# For complete instructions, tutorials, and further information, 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
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
...OPENCLAW
OpenClaw support for Arduino UNO Q Sound Sensor is coming soon.
...OPENCLAW
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.