Ganesh Selvaraj

Normal DC motors just require power supply(+V and GND) and are controlled by switching it ON/OFF or by varying the amount of power supplied to it but in case of servo motors we generally need a microcontroller to control them since it needs a special signal along with the normal power supply(+V,GND and SIG). This circuit will show how to control a servo without using a microcontroller. The circuit uses a 555 Timer IC which is very cheap when compared to a microcontroller and also which doesn’t require programming. The 555 IC is configured in Astable Mode to generate the “Special Signal” for the servo motor to work. First let us understand that signal. Here the special signal is nothing but a Pulse Width Modulated signal usually with a frequency of 50Hz (i.e. a Time Period of 20msec) or 25Hz (Time Period 40msec). 

In this tutorial we’ll learn how to interface a 4-wire Resistive touch screen with ATmega16 microcontroller. Touch screens are two dimensional input devices. Nowadays most of the electronic gadgets use them. Laptops, smart phones, tablets and even some home appliances like washing machines & microwave ovens also use a touch screen nowadays. Touch screens are preferred over keypads because they need very little or no pressure to operate whereas the Keypads/ buttons need a minimum pressure to operate and our hands start aching after some time of continuous usage.One more great advantage in using a touch screens is that it enables us to make more room for the screen itself instead of wasting the space on the permanent keypad. That’s the reason for our smart phone’s screens to become big enough to browse web pages also and still fit in our pockets.

This article will show you how to make your own Serial Port Communication software interface (which is basically a Windows Form Application) using Microsoft Visual Studio 2012. This can be used for both wired (USB to UART/USB to Serial) and wireless (Bluetooth) serial communications. We’ll test the software using an ATmega16 development Board or an equivalent circuit. You may ask “why to create my own interface when there are software(s) already available?” The answer is simple. Developing your own software enables customization which is not possible with commercial software(s). For example, take the project “Wireless PC Controlled Robot Using Bluetooth”. We had to enter specific alphabets and click “send” every time to control the robot. What if instead you had buttons neatly marked “FORWARD”, ”REVERSE”, etc. which when clicked changes the motion of the robot? You can even add  your name and your favourite logo on the interface panel. 

Ever wondered how your Air Conditioner or Heater or Refrigerator adjusts its temperature automatically? The answer is A Temperature Control System. This article will show you how to build a model of such temperature control system using minimum components and without any complex circuit. First, let us learn few terms. Control System is a combination of various physical elements connected in such a manner so as to regulate/direct/command itself or some other device/system. Feedback is a fractional part of the past/present output which is fed back to the input. In case of positive feedback, it is added to the input and if it is negative feedback then it is subtracted from the input. Depending on feedback it is divided into two types:-Open Loop Control System(Feedback is not present), Closed Loop Control System(Feedback is present). Keep on reading to find out what the system consists of and how it is made. 

In the previous tutorial I have explained how to setup a basic serial connection between an Atmega16 controller Board and a computer/laptop. In this article we’ll learn how to control a robot using the computer/laptop wirelessly through Bluetooth. Let us start with the hardware assembly part first. It should be simple since we are using a ready-made chassis. Start by attaching the motors and castor wheel to the chassis. The components needed for the project are : Atmega16 development board with 16MHz crystal, Serial Bluetooth Module(AUBTM/HC-05/HC-04/BLUSMIRF), PC/Laptop running Windows XP/7/8, USB Bluetooth(Not required if you laptop/PC has inbuilt hardware), Motor Driver L293D, 2 X 12V 100RPM Geared DC motors, 2 X Wheels, Chassis, Castor wheel, Female jumper wires. Keep on reading to find out how the robot is constructed and what coding does it use to operate. 

This project would give you a general idea about how to setup and interface any Bluetooth modem with your computer. There are many types of Bluetooth modems available in market, which vary in quality, cost, range, etc. Some of the well known Serial Bluetooth modems are AUBTM, BLUESMIRF, RN-41, HC-05 and HC-04.I would be using the last one i.e. the cheap Chinese Bluetooth module. It has limited functions and it can only work in slave mode. (Remember: Two slave modules cannot directly communicate to each other so be careful when you buy them.) The top range modules have a facility to work in both MASTER and SLAVE modes. It is Class 3 module so it range is very low. (Class 2 has a range of 10 meters and Class 1 has a range of 100 meters.) 

Ever wanted to gift something “Electronically Special” to your loved ones? This article will show you how to make such gift in an Engineer’s style. All we need is a 555 Timer IC and a couple of other electronic components to make this LED Heart Flasher.Basically, the 555 Timer IC is made to work as an “Astable Multi-vibrator” here. We need at least 12 LEDs to make the shape of a heart and a 555 IC is not capable of directly driving 12 LEDs at a time. So that is why we have used a medium power transistor 2N3019 which can drive loads up to 1 Ampere. The transistor works as a switch here and the output from the 555 IC provides the switching signal to the transistor. We’ll be driving the circuit using 6 volts.And one more advantage of this circuit is that you can customize the frequency and Pulse width of the signal by changing the value of the resistors and capacitors  

You may have come across many schematics and projects about a cell phone controlled land rover in many websites. But this is not the same.This article will show you how to make a cell phone controlled land rover without using a micro-controller. You read it right we are not going to use any kind of costly micro-controller for making the rover. Well you must have already come across the usual advantages of cell phone controlled Robot like, interference free communication, long range, etc. The motor driver L293d can control 2 motors bi-bidirectionally and has 4 inputs. The 4 outputs from the decoder IC is fed into the 4 inputs of the motor driver directly without using complicated circuits. Let’s see what’s more beneficial in this robot: Reduced circuit complexity, no need of any Programming, cost is highly reduced. Not everyone can afford a microcontroller along with its programmer and debugger boards. 

Fastest Finger first circuit is basically used in quiz type games where the reaction speed of a participant is significant. The circuit enables us to identify who responded first to the question by triggering a visual and audio indication. The circuit uses a buzzer to produce the audio signal and a seven segment display for visual indication. The display shows the corresponding team number which pressed the buzzer first. The brain of this circuit is an ATMega16 microcontroller which can run at a maximum speed of 16MHz and so there will be no question of clash between any two contestants until and unless their reaction time was same in order of microseconds which is impossible. Continue reading to find out what the circuit components are and how it is assembled as well as put to work.