Project Hub /Security Surveillance & Defense/Intrusion Detection Systems/Motion Sensor With Voice Alarm Using Arduino

Intermediate

ARDUINO

₹500 – ₹1,500

3 – 6 Hours

Partial Kit

Motion Sensor With Voice Alarm Using Arduino

A simple and inexpensive Arduino-based motion sensor alarm that triggers a pre-recorded voice alert when human movement is detected.

Originally published on ElectronicsForU

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

Arduino Nano C Type V3 ATMEGA328 with Soldered Headers Rs. 608.00
PIR Motion Detector Sensor Module HC-SR501 Rs. 153.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: Passive Components (generic)
Speaker / Audio Amplifier
Custom PCB / PCB Fab

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How It Works

The Motion Sensor With Voice Alarm Using Arduino is designed to detect unauthorized movement and output a pre-recorded audio warning. At the core of the system is an Arduino Nano, which acts as the central processing unit. Movement detection is handled by a PIR (Passive Infrared) motion sensor. The PIR sensor monitors ambient infrared radiation levels in its field of view; when a human body passes by, the sudden change in infrared energy generates a digital trigger signal sent to one of the Arduino Nano's digital input pins. Upon receiving this trigger, the Arduino executes its programmed routine, utilizing the PCM library to process and output a stored digital audio file as a pulse-width modulation (PWM) or analog audio signal. Because the microcontroller's native output pins cannot directly drive an acoustic transducer, the audio signal is routed into an LM386 audio amplifier circuit. The LM386 amplifies the weak audio voltage to a sufficient level to drive an 8-ohm speaker, producing an audible voice alert. The entire circuit is powered by a stable 12V DC power supply or battery, which provides the necessary voltage rails for both the logic components and the analog audio amplification stage.

Why Build This

Design and prototype a standalone micro-controller-based intrusion detection system for undergraduate engineering prototyping portfolios.

Integrate digital sensor logic with analog audio amplification stages using discrete integrated circuits like the LM386.

Implement software audio playback techniques on resource-constrained microcontrollers using specialized libraries.

Real-World Application

Home security systems, outdoor monitoring, backyard intrusion detection, and automated warning systems.

Skills You'll Learn

PIR sensor interfacing

digital input state polling

audio signal amplification with LM386

PCM audio playback on microcontrollers

PWM audio generation

power supply distribution

Safety Precautions

Ensure proper wiring and connections before powering the circuit with a 12V DC supply or 12V battery.

Technology Tags

ARDUINO

PIR MOTION SENSOR

LM386 AUDIO AMPLIFIER

AUDIO PLAYBACK

PCM LIBRARY

SECURITY ALARM

Frequently Asked Questions

Can I use a different microcontroller instead of the Arduino Nano?

Yes, other ATmega-based boards like the Arduino Uno will work, though the Nano is chosen for its compact size which fits easily onto custom PCBs.

How is the voice recording loaded onto the Arduino?

Audio data is typically converted into a header file or array using software tools and stored directly within the Arduino's flash memory to be played back via the PCM library.

What is the purpose of the LM386 in this circuit?

The Arduino Nano can generate the audio waveform, but its pins cannot supply enough current to drive an 8-ohm speaker directly; the LM386 amplifies the signal to a usable volume.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

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