Hai Prasaath K

Like Line following robots are fun, making a wall following robot is even more exciting. A wall following robot is designed to move along a wall without hitting it. It has obstacle detection sensors mounted on the body which detects wall and drive DC motors attached to the wheels such that the robot keeps moving along the wall.The robot can be designed right oriented or left oriented or even can be designed to follow either sides. A right or left oriented wall follower can be designed easily with the help of just two sensors. Though more sensors can be used in making such a robot which will ultimately improve the path accuracy of the robot.

The computing devices have evolved to great extent in the past decades and so the software technology too. The computing devices all over the world can be broadly classified as Desktop computers & Laptops, Mobile devices, Servers, Mainframes, Supercomputers and Embedded devices. Any computer has two essential components – Hardware and Software. The software is broadly classified to two types – Operating System and Applications.  

In the previous tutorial – Introduction to Linux, Linux was introduced as popular open source operating system with vast scope in desktop, server and mobile computing environments. Linux being open source and immensely popular among OSS developers and advocates, there are hundreds of Linux Distributions available at present. Any Linux distribution or package is a complete operating system software having Linux Kernel, GNU utilities, Shell, desktop environment and some default applications bundled together. 

In the previous tutorial, Linux with all its integral components was examined on the lines of being a complete open source operating system. Many different Linux distributions (also called Distros in short) were also very briefly mentioned at the end of the previous tutorial. There are hundreds of Linux Distros there and it can be intimidating to choose one, when, all it matters is, to have just a sound beginning. An almost exhaustive list and links of available Linux distributions can be checked on DistroWatch.com.  

In the previous tutorial, a Raspberry Pi desktop running Raspbian (a Debian based Linux Distribution) was successful, setup. Now it’s time to start shell scripting and get the hands dirty with the very first shell script.      

In the previous tutorial, Bash Shell and LXterminal to launch Linux Console for the bash shell in Raspbian, was demonstrated. Now, it’s time to start shell scripting using bash shell.The shell scripts are made up of shell commands. The shell commands in the bash shell are called bash commands after the name of the respective shell. The shell commands and their syntax remain more or less the same irrespective of the shell. So, bash commands and their syntax is almost similar to shell commands for any other Linux shell like Csh, Ksh, and Tcsh etc. 

Robots are designed to ease and automate the work of humans. They are useful to deploy at places which are not easily accessible. In this tutorial, a humidity and temperature monitoring rover based on IoT’s robotic application is designed. Humidity and temperature are the most common physical environments that are needed to be monitored. The four-wheel robot designed in this project can be operated in a range of 30 Metre and can withstand a temperature up to 150 degree Celsius. The robot can be controlled through a mobile phone which will have a custom app installed on it. The mobile will connect to the robot via Bluetooth.

In this tutorial, a spy rover controlled through Bluetooth is designed. It is a surveillance robot which will be used to monitor and keep watch of areas not easily accessible by humans. Surveillance is the process of monitoring a situation, an area or a person. It is generally practiced in a military scenario where surveillance of borderlines and enemy territory is essential to for the country’s safety.Human surveillance is achieved by deploying personnel near sensitive areas in order to constantly monitor changes. But humans do have their limitations, and deployment in inaccessible places is not always possible. There are also added risks of losing personnel in the event of getting caught by the enemy.

Home Security Systems are a need of the modern day houses. It is possible to design a simple home security solution by using Raspberry Pi and utilizing the power of Internet of Things. The home security system designed in this project is a simple and easily installable device built using Raspberry Pi 3, Web Cam and PIR Motion Sensor. The Raspberry Pi 3 Model B comes equipped with on-board Bluetooth (BLE) and Wi-Fi (BCM43438 Wireless LAN), so, it can be easily connected with a Wi-Fi Router to access a cloud service. 

In the previous tutorial, gate level minimization of boolean functions was discussed. A boolean function must be expressed in standard form as either sum of products (SoP) or product of sums (PoS). Once a boolean function in case is minimized to SoP or PoS form, it can be easily fabricated as two-level implementation of AND and OR gates. A two-level implementation is preferred so that there is minimum delay in signal propagation through logic gates from input to output of the digital circuit.  

In the previous tutorials, boolean functions, boolean expressions, minimization of boolean expressions and implementation of a boolean function into logic gate diagram was discussed. It is possible to minimize a boolean function with less number of boolean variables and implement a logic gate diagram for it manually. But as the number of variables in a boolean function increases, not only its minimization becomes complex, designing a logic gate implementation for it also becomes cumbersome. In such case, computer based design tools are the ultimate resort.

The previous tutorials laid the foundation for logic synthesis and design of digital circuits. The digital circuits in general always have application as computing devices either as processor, controller or application specific ICs. As a computing device, the digital circuitry of a processor, controller or ASIC must be essentially able to perform arithmetic operations. The implementation of arithmetic operations by digital circuitry is further used to build up complex computing logics and mathematical functions. 

In the previous tutorial, the basic combinational arithmetic circuits like half adder, full adder, half subtractor and full subtractor were discussed in details. Now, in this tutorial, the truth table and derivation of the boolean expressions for all those circuits will be considered. With the derived boolean expressions, all those circuits will be practically designed using digital ICs.  

In the first tutorial of this series – Introduction to Digital Electronics, it was mentioned that there are different code systems that are used to represent digital information as binary numbers. Each code system has different binary numbers assigned to same symbols and characters. The different digital systems may be using different code systems. In such case, there must remain some code conversion circuit to make the interconnected digital systems compatible. 

In factories and industries it is common to deal with the use of harmful and poisonous gases. There are situations in which the concentration and volume of these type of gases need to be monitored in an apparatus. Because these gases can be harmful to humans, it is not safe to employ humans for such tasks.So, robots can be used monitor different parameters related to the use of such gases in an apparatus or gas filled chamber. In this tutorial, a wireless robot is designed which can move inside a chamber or well and detect the level of concentration of the gas at the spot. 

Robotic cars are commonly used for outdoor operations. These are designed for different purposes and applications. These robotic vehicles are meant to move over a surface and reach a spot to carry out the intended application or perform specific tasks. The robotic cars can be controlled with a remote control which may be connected to the robot either through a wired connection or a wireless interface. The wireless connectivity is usually provided by Wi-Fi, Bluetooth, RF or mobile networks. One of the RF technologies available for providing wireless connection is Zigbee.  

The Robots are mechanical devices equipped with software based intelligence that can perform specific physical tasks. There are many kinds of robots and robotic applications. The robots are designed to suit their application and their mechanical design, body, electronics, and software are designed accordingly.The robotic vehicles or robotic cars are one of the many types of robotic designs. The robotic cars are designed to move around plain surfaces where they can perform certain tasks either through remote controlling or autonomously. They are equipped with sensors, control circuitry and actuators for their operation.

In robotics, wireless robots are commonly used for applications that need to be operated remotely. Usually such robots are controlled with a remote control that connects with the robot using a wireless technology like RF, Zigbee, Bluetooth, Wi-Fi or Mobile network. In this tutorial, a wireless robot will be designed that will connect with the remote control using 434 MHz RF module.  The remote control will have a keypad to control the movement of the robot. Keypads are one of the commonly used Human Machine Interfaces (HMI) and play an important role in small embedded systems where human interaction or human input is needed.Matrix keypads are well known for their simple architecture and ease of interfacing.

In one of the previous projects “Hand Gesture Controlled Wireless Robot”, it was discussed how remote controls with switches or buttons used for controlling wireless robots have a disadvantage in controlling the robot due to response time factor of the human handling it. As a solution to the problem, use of advanced human-computer interfaces like the gesture recognition, eye movement tracking, and brain waves was suggested. Of which, hand gestures were used in the previous project to control the robot. In this tutorial, a wireless robot will be designed that will be controlled by the joystick. A joystick is not a new input device but it provides better control over the subject. It is easier to use and handle by a human operator.