Hi all, welcome back, In the previous post, I told you how an IR sensor works and how to make a line follower using an IR sensor. Now, i will show you how you can make a Simple DIY Burglar Alarm using an IR sensor and a Buzzer without using any micro controller or complicated coding.

About Our Sponsor – UTSource

To start with, UTSource is a Shenzhen based electronic component distributor and is one of the largest electronic component distributors across the world.

UTSource started as a small business to grow to over 10 million customers with around $150 million in sales. With a huge collection of different products being distributed at UTSource, it can range from semiconductors to transistors to providing design-chain services.

UTSource promises to provide only the best quality products to its customers. All products on the sail are said to be original and certified. Purchased directly from manufacturers and authorized agents.

DIY Burglar Alarm Components Needed

To set up this, you need the following components only;

IR sensor
Breadboard
Buzzer
Some connecting Wires
5 Volt Power Adapter

IR Sensor Burglar Alarm Video Tutorial

Watch this video on YouTube

DIY Burglar Alarm Tutorial

Sponsor Link

This Project is Sponsored by UTSource. UTSource is a professional electronic components supplier.

About IR Sensor

If you are a beginner and new to Electronics and Robotics, you might have heard about IR Sensor many times.

IR sensor consists of two parts ;

an IR transmitter (IR LED)
an IR receiver (Usually a photo diode)

Most IR Sensor will have 3 pins;

VCC (5V)
GND (0V)
Vout (Output Voltage).

VCC will power up the sensor circuit. Output voltage is taken through Vout pin when IR rays are reflected back to the photo diode.

IR LED always emits IR rays to the direction it is pointing to. Now let us bring it closer to a surface. When the IR rays hit a surface, some rays will reflect back depending upon the color of the surface.

ie, Brighter the color, more IR rays will be reflected back. Darker the color, more IR rays will be absorbed by the surface and lesser IR rays will be reflected back.

IR Sensor Working DIY Burglar Alarm — IR Sensor Working

The Photo diode will receive the reflected rays. The resistance of the photo diode varies depending upon the intensity of the received IR rays. And thereby changes the output voltage.

Thus it is possible to sense the brightness of the surface by looking into the reflected IR rays.

Let’s get started…

This is a very simple project. You just need maximum 1 minute to set up this.

Now you know how an IR sensor works. We will start building our own Burglar alarm.

Here I will bend the legs of LED and photo diode so that they are facing each other. I will show you in the procedure.

Step 1 : How to Order Quality Products from UT Source?

Ordering the products from UTSource is easy. First thing to do is head over to the UTSource website and create a free account!

About the product categories, there is a category-based component listed in UTSource with a clear indication of a number of components grouped under each category.

If you wanna see subcategories under each of these categories you can scroll past these main categories and below that you can find the subcategories under each main category.

Next thing to do is search for the component you want on the search box.

Scroll down the page and find the product you want and add the product to your cart.

Once you have added all the products to the cart, you can go to the cart to see all the components. In the cart, you can see the estimated charges for different courier services. You can also add or remove more products from the cart.

Once you click checkout, you can click on Checkout. Here you should provide the delivery address as well as the Shipping method.

Once it is done, click on Submit order and complete your payment. That’s it! You will get the product within the mentioned time period.

Step 2 : Burglar Alarm Circuit Connections

The 5 V supply is connected to the IR sensor and the IR sensor Output is connected to the Buzzer.

IR Sensor
Vcc – 5V
Gnd – Gnd
Vout – +ve of Buzzer

Buzzer
+ve – Vout of IR Sensor
-ve – Gnd

You can use a breadboard to connect all of them together.

Step 3 : Fixing it on the Door

I have cleaned all the connection using a zip tie and this is what it looks like.

Now we can fix this on the door frame and power it up.

Now we need something to block the IR rays from LED from reaching the photodiode. For that you can use a black cardboard or a tape.

We can fix this on the door in such a way that when the door is closed, it will be placed in between the photodiode and the IR LED.

Working of Burglar Alarm

When the door is closed ;

The photo diode will be facing the black surface and no IR rays will be reaching the photo diode. Hence the output of the IR sensor will be Zero.

When the door is opened ;

The photo diode will be facing the IR LED and the IR rays will be directly hitting the photo diode. This will cause the output voltage go high and the buzzer connected to the output of IR sensor will start to beep.

New to Robotics?

We have a beginners guide on “Getting Started with Robotics” which will give you a kick start in this field. Check out our free video tutorial below for a brief introduction.