The mixing of colours has always been an
intriguing phenomenon in the field of science. This project mainly deals with
colour models. Using only three colours namely red, green and blue (RGB) we produce
over 16 million variety of colours. Here, I showed how a simple communication
protocol like MQTT can be used to manipulate the remotely placed light emitting
sources to display the beauty of the world. I use ‘Node MCU’, an open source LUA based firmware for the purpose of
communication between the clients. The goal of this project is to show how we can establish the communication from broker to clients by using a lightweight
messaging protocol. The applications of this project is vast as all the digital
systems use RGB displays. Also, a significant texture to the photographs, video
graphs and arts has been provided by the RGB models.
Problem Statement
A digital monitor or digital displays are made up of
tiny units called pixels. These pixels are comprised of three light units, one
for red, one for green, and one for blue. We can’t use CMYK models. So, here I'm defining a technique to mix these colours well-known as RGB colour model.
Objective of the project
The main purpose of the RGB colour model is for
the sensing, representation, and display of images in electronic systems, such
as televisions and computers, though it has also been used in
conventional photography. Before the electronic age, the RGB colour model already had a solid theory behind
it, based in human perception of colours.
The RGB colour model mapped to a cube. The horizontal x-axis
as red values increasing to the left, y-axis as blue increasing to the lower
right and the vertical z-axis as green increasing towards the top. The origin,
black is the vertex hidden from view. It also deals with the colour management.
The primary goal of colour management is to
obtain a good match across colour devices; for example, the colours of one
frame of a video should appear the same on a computer LCD monitor, on a plasma TV screen, and as a printed poster. Colour
management helps to achieve the same appearance on all of these devices,
provided the devices are capable of delivering the needed colour
intensities.
Description of communication protocol
used
MQTT stands for MQ Telemetry Transport. It is a publish/subscribe,
extremely simple and lightweight messaging protocol, designed for constrained
devices and low-bandwidth, high-latency or unreliable networks. The design
principles are to minimise network bandwidth and device resource requirements
whilst also attempting to ensure reliability and some degree of assurance of
delivery. These principles also turn out to make the protocol ideal of the
emerging “machine-to-machine” (M2M) or “Internet of Things” world of connected
devices, and for mobile applications where bandwidth and battery power are at a
premium.
The MQTT protocol defines two types of network
entities: a message
broker and a number of clients. An MQTT broker
is the server that receives all messages from the clients and then routes the
messages to the appropriate destination clients. An MQTT client is any
device (from a micro controller up to a full-fledged server) that runs an MQTT
library and connects to an MQTT broker over a network.
About Node MCU
NodeMCU is an
open source IoT platform. It includes firmware. The term "NodeMCU" by default refers to the
firmware rather than the development kits. The firmware uses the Lua scripting language. It is based on the eLua
project. NodeMCU
is able to support the MQTT IoT protocol, using Lua to access the MQTT broker. A microcontroller (MCU for microcontroller unit) is a
small computer on a single metal-oxide-semiconductor (MOS) integrated circuit chip. Some microcontrollers may use four-bit words and operate at frequencies as low as 4 kHz, for low power consumption (single-digit mill watts or microwatts).
Selection and Description of software
“Adafruit.io” is a cloud service. It can handle and visualize
multiple feeds of data.
Specifications of Adafruit io include:
- Display our data in real-time, online.
- Makes our project internet-connected: Control motors, read sensor
data, and more!
- We can connect projects to web services like Twitter, RSS feeds,
weather services, etc…
- Connects our project to other internet-enabled devices
Block Diagram
*Schematic representation of working of Node MCU
Components
Required
·
Node MCU
·
Light emitting diodes(Red, Green, Blue)
·
Mobile to send input
·
Power supply
·
Jumper cables
·
Wi-Fi Connectivity
·
Breadboard
Circuit
Design
Simulation
by using Labview
Result (output obtained)
RGB Colour
Model
RGB colour model is an
additive colour model in which red, green and blue colours are mixed together
in various proportions to form a different array of colours. The name was given
with the first letters of three primary colours red, green and blue. In this
model, colours are prepared by adding components, with white having all colours
in it and black without the presence of any colour. RGB colour model is used in
various digital displays like TV and video displays, Computer displays, digital
cameras and other types of light-based display devices.
RGB is also called an "Additive" colour system,
because it starts at black, and then colour is added.
RGB models have a wide range of applications namely in
the field of photography, art, televisions etc…
Advantages
·
Allocate more
quantization levels to the areas of colour space that correspond to the low
spatial activity.
·
Perceptually
weighted distortion metric as a cost function .
·
A method that
tries iteratively reduces false contouring after pixel mapping phase.
·
No transformations required to display data on the screen.
·
It is considered as the base colour space for various applications.
·
It is a computationally practical system.
·
With the help of additive property, it is used in video displays.
·
It relates simply to CRT applications.
·
This model is very easy to implement.
Applications
1. RGB models in display : The main application
of the RGB colour model is to display digital images. It is used in cathode ray
tubes, LCD displays, and LED display such as television, computer monitor or
large screens. Each pixel on these displays is built by using three small and
very close RGB light sources. At a common viewing distance, these colours
cannot be distinguished separately and viewed as a single solid colour.
RGB is also used in component video display signals. It consists of
three signals red, green and blue which carried on three separate pins or
cables. These types of video signals are the best quality signal which can be
carried on the standard SCART connector.
2.
RGB in Cameras : Digital cameras for photography that use a CMOS or CCD
image sensor mostly perform with some type of RGB colour model. Current digital
cameras are equipped with an RGB sensor which helps to perform the evaluation
of light intensity in a crucial manner. And this results in the optimum value
of exposure in each image.
3.
Philips HUE : Philips
Hue is a line of colour changing LED lamps and white bulbs which can be
controlled wirelessly (smart bulb).It generates around 16 million colours
wherein widely used in IOT applications or to make home smart. It also uses MQTT
as its main communication protocol.
Conclusion
Scientists found three
colours namely red, green and blue which produce many other colours while
mixing. They called these colours as primary colours. When combined red and
green produce yellow, blue and green produce cyan, red and blue produce
magenta. And this technology is later made as a colour model and is named as an
RGB colour model.
The main purpose of this
colour model is for the sensing, representation, and display of images in an
electronic system. The evolution of the RGB colour model creates a huge
development in the digital field. It was used in different electronic devices
like TV, monitor, cameras, printers, etc.
So,I hereby by focusing on
the pros, designed such a model that has a great significance in this digital
and colourful world. I also represented how to control a remotely present
light sources just by using a lightweight protocol like MQTT through Wi-Fi.
Guided by :
Kavyashree M K
Professor @JSSSTU,Mysuru.
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