**3. Li fi –transmitter and receiver**

The operational procedure of Li-Fi is very simple, it transmits binary 1, if the LED is in on condition, if the LED is off, it transmits a binary 0. The switching of LEDs between on and off positions can be implemented very quickly, which gives wonderful chances for data transmission. A controller which is used to program the LEDs and some LEDs are mainly needed. To implement the Li-Fi technology, it is required to just vary the LED's flicker rate based on the data we need to encode. All the data on the internet will be streamed on one end to a lamp driver when the LED is switched on the controller which converts the digital data in form of light. At the receiver end, the received signal is converted back to original signal with the help of a light sensitive device (photo detector). This method of wireless transmission of data using rapid pulses of light is technically denoted as Visible Light Communication (**Figures 2** and **3**) [5].

**Figure 2.** *Top view of Li-Fi transmitter and receiver.*

**Figure 3.** *Bottom view of Li-Fi transmitter and receiver.*

#### *IoT Applications Computing*

Light based Wi-Fi is called as Li-Fi. It uses light signal instead of radio waves for data transmission. Li-Fi uses transceiver-fitted LED lamps instead of Wi-Fi modems. Transceiver-fitted LED lamps can be used to light a room as well as transmit and receive information [5]. Power supply is used to provide power to the transmitter and receiver section. Data stored in the controller is transmitted through a Li-Fi LCD display that is used to check whether the data is transmitted and received. Microcontroller is used to control both transmitter and receiver sections. A controller used in both transmitter side and receiver side. Using Proteus software tool program written to microcontroller. Li-Fi is a term used to describe the visible light communication technology applied to high speed wireless communication (**Figures 4** and **5**).

#### **Figure 4.**

*Working module of Li-Fi Tx and Rx via LED.*

**Figure 5.** *Li-Fi transmitter.*

*Vehicle Collision Avoidance System Using Li-Fi DOI: http://dx.doi.org/10.5772/intechopen.98616*
