Li-Fi [Audio Transmission Through Light]

Hello Friends ! Today we are going to perform an experiment on Li-Fi . First I'm going to tell you in brief about LiFi.

The full form of LiFi is Light Fidelity. LiFi basically is a Wireless Communication Technology which uses Visible Light for Data transmission. LiFi is designed to use LED Light Bulbs similar to those present in our homes and offices. However, there is a slight difference in these LiFi LED Light Bulbs and Normal LED Light Bulbs . These LiFi LED Light Bulbs transmit Data through the Light given off by them and these Light Signals are received by Photoreceptors. Now a question in your mind will arise that what is a Photoreceptor. So in terms of Technology, a Photoreceptor is a Sensor that detects Light by capturing Photons (Photons are Light Particles). In Labs, with stronger LED's and Powerful Technology Researchers have gained speeds upto 10 Gigabits per Second (10 Gbps) through LiFi . So Let's Get Started -

Step 1: Gathering the Materials

This Experiment will not cost you more than 7 Bucks and the best part of this Experiment is that you don't need any Arduino or Programming. We need very simple materials for it. The List of the Materials is given below -

1. 3.5 mm Jack PIN OUT........( X2 )
2. 1 Watt LED..........................( X1 )
3. 9 Volt Battery......................( X1 )
4. 9 Volt Battery Connector...( X1 )
5. 100 Ohm Resistor..............( X1 )
6. 5 - 6 Volt Solar Panel.........( X1 )

Some basic tools are also required for this Experiment. The List is given below -

1. Soldering Iron
2. Hot Glue Gun ( Not Necessary Super Glue will also work )

Step 2: Preparing the 3.5 Mm Jacks

NOTE: If you get wires Pre-Soldered on the jack then you can simply skip to the Next Step but If you get the Jack only then follow this step.

First we are going to get our Jacks ready. In a 3.5 mm Jack you will find 3 parts (Terminals) as shown above.

The Highest Part is known as GROUND.

The next 2 Shorter Parts are known as LEFT and RIGHT

1. Unscrew the Cap on the Top of the Jack
2. Solder a wire on the GROUND first.
3. Then Strip a wire longer from the front and solder it on the both shorter parts ( LEFT and RIGHT ) from one side only
4. Pass your both wires through the hole on the cap and screw it back on
5. Repeat the same steps for the other jack too and your both Jacks are ready to go

Step 3: Building the LiFi Transmitter

Now we are going to build the Transmitter which will emit the LiFi Signals

I've Given the Circuit Diagram for the Transmitter above

Steps for building the Transmitter are given below -

1. Connect the Negative (-ve) Terminal of your LED with the GROUND terminal of the Headphone Jack
2. Now, Connect the Resistor to the Positive (+ve) Terminal of the LED
3. Connect the Positive (+ve) Terminal of your 9 Volt Battery with the Resistor
4. Now at last connect the Negative (-ve) Terminal of the Battery with the common wire of LEFT and RIGHT Terminals from the 3.5 mm Jack to Complete the Circuit.

So, We've made the LiFi Transmitter and now its turn to make the receiver that will Receive these LiFi signals

Step 4: Building the LiFi Receiver

In the last step we made the Transmitter of LiFi signals and now its turn to make the Receiver to receive these LiFi signals.

The Circuit Diagram is given above for the Receiver

The Steps for making the Receiver are given below -

1. Solder the wires to the Positive (+ve) and Negative (-ve) Terminals of the Solar Panel
2. Now, Connect the Negative (-ve) Terminal to the GROUND Terminal of the other Jack
3. The Positive (+ve) Terminal is left so connect the Positive (+ve) Terminal of the Solar Panel to the Common wire of LEFT and RIGHT Terminals from the jack to complete the Circuit.

Now our Receiver is also built and the only thing left is to assemble both the circuits in a cardboard box.

Step 5: Building the Cases for the Transmitter and Receiver

We have completed the Circuits of the Transmitter and Receiver and now its turn to make Protective Case for them. By this our Project will look neat and will be safer than open Circuits.

Transmitter Case

1. Cut out the pieces of Cardboard as per the measurements given above or you can use wood too but I recommend Cardboard as it will be easier to work on. (Note: The Templates are not by correct measurements they are for reference only)
2. Now get your Glue Gun ready
3. Make a L shaped Structure with the 2 bigger pieces of Cardboard
4. Attach the Cardboard Supports on both sides of the L joint to make it more stable
5. Place the Battery near the inside of joint
6. Make a hole on one of the big cardboard pieces (almost in the center)
7. Pass the LED through the hole and glue it there
8. Glue the resistor and wires according to the empty space left
9. Glue the wire of the Jack at the end of the Lower cardboard and the Transmitter is ready to go

Receiver Case

1. For this case we will glue the supports on the ends of the solar panel and our receiver is also ready to go. (Note: The Templates are not by correct measurements they are for reference only)

Now our all setup is done and if anything left, that is just to test it.

Step 6: Testing Time !

All of our Setup is done and now we are going to test it.

1. Take the LiFi Transmitter Jack and Connect it with your Phone through the 3.5 mm Female Jack
2. Take the LiFi Receiver Jack and Connect it with a Pre-Amplified Speaker in the AUX Input Port
3. Place the LiFi Transmitter and LiFi Receiver Face to Face with each other with a Distance of about 5 cm ( or 2 inches ) between them.
4. Connect the Battery to the 9 Volt Battery Connector in the LiFi Transmitter
5. The LED will Light up
6. Play any song on the Connected Phone

You will observe that the song will also start to play on the speaker too!

This happens because The LiFi Transmitter will transmit the audio signals from your Phone through Light from the LED to The LiFi Receiver that is the Solar Panel. The Solar Panel will collect these LiFi Signals and send them to the Speaker. Then the Speaker will amplify these LiFi Signals and convert them to Audio Signals again.

Step 7: Some Problems Are There ......

This may happen that some Problems occur with your setup. I've Listed some reasons below why this must be happening -

1. Your Connections are wrong or are not soldered properly
2. Your Components are damaged
3. Your Phone's Headphone Jack may be damaged
4. Your 9 Volt Battery's Charge may be low
5. Distance between the Transmitter and Receiver is large
6. Volume of the Speaker or the Phone is low
7. Other Lights are causing interference, try covering the setup or switch off the Light of the room

If you are still having some problems regarding this feel free to ask questions

Hope you enjoyed the Experiment and Keep Experimenting and Discover New Things

Stay tuned for more such Interesting Experiments and Creations