Do you know you can catch a thief using an IR sensor? But wait, what’s IR sensor?

IR stands for Infrared rays. These rays are the source of energy in the form of light invisible to human eyes. IR rays are a type of electromagnetic radiation and their wavelength lies between 700 nm to 100,000 nm.

Infrared sensor or IR sensor is an electronic circuit that works on the principle of Infrared light emission and reflection to detect an object, distance and motion.

Let’s do an experiment

Things you need:

You will need the following of the Havi Elements.

1.  Power
2.   IR
3.   Buzzer

Prepare the circuit as shown here.

Did you know: Infrared was discovered by Sir William Herschel in 1798.

The experiment
STEP 1: Connect the Power element, IR element, and buzzer element. (IR element has a transmitter, receiver, and control portion)
STEP 2: Switch on the power element. As soon as the energy reaches the IR element, it will release the infrared rays.
STEP 3: Place an object in the path of infrared rays and the buzzer will start making the sound.

Why does it happen?

The IR element has two types of LEDs. The transparent one is the transmitter and the black LED is the receiver. The transmitter sends infrared light. When infrared light strikes the object it gets blocked and hence is reflected. The reflected lights are received by the receiver. The receiver senses the rays coming back and that gets noticed by the control portion of the IR element.

The IR element has two types of LEDs. The transparent one is the transmitter and the black LED is the receiver. The transmitter sends infrared light. When infrared light strikes the object it gets blocked and hence is reflected. The reflected lights are received by the receiver. The receiver senses the rays coming back and that gets noticed by the control portion of the IR element.

The IR then lets a “YES” signal pass. The buzzer listens to that YES and follows it as a command to make the “noise”. Interesting, no?

What objects can IR detect?

Any object that reflects the light will activate the IR and make it pass the “YES” signal. But what about the transparent objects like

1. Glass
2. Water
3. Plastic
4. Colored water

All these objects may or may not reflect the IR light. Actually, it depends on the quality or say transparency of the objects.

Say a glass, if very pure and let’s pass all of the IR light, will not get detected by the IR signals. Try various transparent, semi-transparent and non-transparent glasses around you.

You can try pouring some water in front of the IR element, like creating an artificial waterfall, and see how IR reacts.

Can only an IR transmitter send the IR light?

To answer that, check your element circuit into the sunlight without blocking the way of the IR LED. What happens? The buzzer will make the sound. That means it has received the “YES” from IR even though you didn’t block it?

So from where the receiver has received the IR light? Huh?

This sun. The sun radiates IR light and is the biggest source of energy for us.
The same is true for fire and high-intensity bulbs and lights. They do emit IR light which the IR receiver detects and pass the “YES” even though there is no object to block the way.

Even your TV and AC remote controls also use IR light. Try to point the remote control against the IR LED and press the buttons, it should send a “YES” signal.

Why don’t we do all these experiments? We have prepared an experiment observation sheet for you. Download this worksheet and fill the details with what you observe.

Experiment Observation Sheet

But How can we catch the thief using IR?

Still, need to explain this? You smart heroes!

Place the IR element near the diamond and if someone lifts the precious stone, the buzzer will make the sound. Which movie have you recalled?

And place the IR near to the door or locker in a way so a body part blocks the IR light flow… and…. Dhen…ten….nen…….

What are the applications of IR?

Infrared is used in diverse sectors in ample ways. The primary uses include tracking, surveillance, night vision, and target location. IR is widely used in the Civil, military, space, and medical domains.

And with this, now it’s your time to create amazing IR projects and helpful inventions.

Heroes you go!