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In an H Bridge you can control the direction of motors from clockwise to anticlockwise. The connections of the H bridge are shown below. H-Bridge                           we have used four transistors to construct the H bridge. The 4 transistors and the load are arranged in the shape of H. Hence it is referred to as H- bridge. case 1: When A and A' are High ( B and B' are Low) when a current is supplied to the base of transistor A and A'. the two transistors start to conduct. Here no current is supplied to the base of transistor B and B'. Hence current flows from A to A'. .which makes the transistor rotate in clockwise direction. case 2: When B and B' are High (A and A' are Low) when a current is supplied to the base of transistor B and B'. The two transistors start to conduct.here no current is supplied to the base of transistor A and A'. Hence current flows from B to B'. which makes the transistor rotate in anti-clockwise direction. Note: For

We use switch in our day to day life to switch ON/OFF a bulb or a fan or  any electrical devices. But when we use switches in digital circuits, we observe a phenomenon called bouncing. This occurs because, when we turn the switch, the mechanical parts vibrate. i.e It toggles between ON and OFF state for some time until the mechanical contact attain equilibrium. this vibrations are minute and are not at all noticeable in electrical circuit. where as in digital circuits, these vibrations create pulses. which are detected by circuits which results in an error.               In the above circuit, there is a switch connected to VCC. You can toggle it between terminal 'a' and terminal 'b'. which as a voltage drop of 'Va' and 'Vb' respectively. In digital circuits if you can observe, it takes a finite amount of time to toggle between terminal 'a' and 'b'. which might approximately take 15ns. Now let us consider the terminal is at 'a'. we

MODEL 1 WATER COOLING SYSTEM TESTING We all have a desktop at our disposal. So one day I came across the idea to overclock my desktop so that I can play games without a lag and will be faster. If you have seen full metal alchemist, you might know what is equivalent trade. Here for the increased in performance, there is an increase in the processor temperature. as the temperature of the CPU increases the the CPU starts to degrade. In other words, the life of the system decreases. to prevent this a proper cooling system must be designed  to keep the CPU temperature in check. The heat sink the manufacturers provide cannot dissipate so much of heat. so I decided to make a better cooling system for my system and ended in making a water cooled system. I took two days to make the first model and 4 hrs to make the second model. with my home made water cooling system, I saw a drop of 12 degree Celsius compared to the conventional heat sinks. the 12 degree temperature drop is a very good number.

In this post we will learn how to use JK flip flop as a latch. i.e. for one pulse, the circuit continues to stay in the ON state until the next pulse. and the circuit continues to be in the OFF state till the next pulse. This can be achieved by using toggle mode in JK flip flop. TRUTH TABLE: IC 7476 J       k       set '      reset'        Q      Q' 1       1        1            1               Toggle IC CD4026 J       k       set       reset         Q      Q' 1       1        0           0               Toggle Note: Set is referred as PRE or preset. Reset is referred as CLR or clear. Refer the Datasheet of the JK flip flop you are using to check whether it is set' and reset' or just set and reset. in the later case you should make set and reset as 0 instead of 1.Example: IC CD4026 has set and reset, whereas IC 7476  has set' and reset'. Refer the data sheet to check whether the JK flip flop you are using is low-high trigger or high to low. accordingly c

A few days ago I went to get components for a project I was building. and came across a 3-axis accelerometer. So I decided to test it and make a post to give you an idea of things work and how you can use it. ADXL 355                   The accelerometer I have is ADXL 355 v2.0 board. there is are 5 headder pins, ground, 5V supply, X-axis output,Y-axis output and Z-axis output. It is quite compact. The one I have measured around 15mm x 15mm. These sensors are low cost. And can be incorporated in Projects or robots we build. The ADXL 355 board I have has an onboard Red led (smd) for the indication of power. The accelerometer has a wide range of applications. ADXL 355 is a basic accelerometer which gives analog values for all the three axis depending upon the position of the IC. ADXL 345 is an advanced accelerometr which can detect free-fall,activity,tap,double tap and communicates via I2C. The ADXL is a a ultra-lowpower as it consumes only 25 uA in measurement mode. the ADXL 355 IC alone

Ever wondered to easily manufacture oxygen using household stuff??? you are at the right place! go and gather the following! Items required: Hydrogen peroxide (H2O2)  Potassium permanganate (KMnO4) Procedure: Now pour a little amount of  Hydrogen peroxide (H2O2) in a small container,never add too much because it is too dangerous and always wear protective goggles and gloves. now add a small amount of  Potassium permanganate (KMnO4). Water vapor and oxygen is released! you can test for oxygen by placing a match stick. I used 6% concentration Hydrogen peroxide (H2O2) you could use a higher concentration to get more oxygen and less amount of water vapor. video:

                I always wanted to spy on people, and one day when i was cleaning my room i came across a old logitech WEB camera and i decided to make something useful using it. and i had a brilliant idea. so i searched for a servo and the arduino and made this simple project which even a school kid can do. Items Required: web camera arduino board servo motor 10K pot Procedure:   first you need to connect the servo to the Analog pin zero of the Arduino board and connect the servo to the Arduino pin 9. Now connect the arduino to the computer and run the arduino software and paste the following code and upload the code now vary the pot, the camera rotates accordingly and you can use the software provided with the webcam to record or take pictures. Enjoy !! Please leave a comment if you try this! :) Video: Code: // Controlling a servo position using a potentiometer (variable resistor)  // by Michal Rinott <http://people.interaction-ivrea.it/m.rinott>  #include <Servo.h>  Serv

INTRODUCTION:                        S.A.T   plate is a new variation in the design of our food serving utensils. This innovation helps us to harvest chemical energy to keep our food warm in the plates which we use to serve the food. This is a simple innovation, yet effective in our day to day life.                       The S.A.T plate is designed to overcome the problems of keeping the food warm for longer duration of time. This invention allows people to have their food and at the same time keep the food warm. Many of us are slow eaters; this means that the food loses its temperature before we complete eating the food. Hence the S.A.T plate is designed to overcome problems like these. WORKING:                          Sodium acetate tri hydrate crystals melt at around 331 K .  Sodium acetate tri hydrate has a special property,  Th at is   when they are heated to around 373K, and allowed to cool, the liquid solution becomes   supersaturated at this poi

In this post I will teach you how to remotely access your rasperry pi from another computer on the same network. we can access the raspberry pi without connecting a monitor, keyboard or a mouse to it. I assume you have downloaded the SD card Image of raspbian "wheezy" or similar. and setup your SD card. By default the ssh will be enabled on the raspbian "wheezy". Now you just need to insert the SD card and plug in the LAN cable or a WiFi Dongle. check the connection once and power it up. now you have to find the internal IP address for the raspberry pi. The common one is to connect it to a monitor and connect a keyboard. power it on and enter user name: pi password: raspberry Now type ifconfig , scroll and find the IP address. usually i will start from 192.168.x.x. note down this IP address. The second method which I discovered was to log in to your WiFi router (I had connected my raspberry pi to LAN using the WiFi router). In this method you need not connect a moni

There are numerous Ways to make Hydrogen gas. It is the main component of water. So I shall show you one technique to make hydrogen gas. Materials required:  Aluminium : I used aluminium pieces which I found in my garage. You can also cut pieces of coke/red-bull can and use NaOH : I took NaOH pellets Water Test tube or conical flask Depending upon how much hydrogen you want to produce. Test tube stand Balloon : select the appropriate size of the balloon. rubber band Source of ignition: To test The hydrogen. Now follow these steps: Step 1: Take the Test tube and fill it with water. Dissolve the NaOH pellets. If you have ready NaOH solution, Then you can use that. Step 2: Now add the Aluminium pieces.(If you want to produce hydrogen faster then you have to use aluminium powder instead of pieces.) Step 3: Tie the balloon to the Test tube using the rubber band. and mount the test tube on the test tube stand. NOTE: The reaction is exothermic. There is a lot of heat produced.So do not try t

First up blinking LED! Blinking LED is the basic and the first thing you should learn.First let us connect the Arduino to the computer. Then start the arduino IDE. if you do not have the IDE, then visit the Arduino Website and download it.when you open the arduino IDE you will see the following window. Arduino IDE Now go to tools, boards and then select the board you are using. I am using a Arduino duemilanove. Arduino Duemilanove Now go to tools, Serial port and select the port to which you have connected. If you dont know the port just select one port and upload the program. If you get an error then change the port until the program gets uploaded. now let us write a program to blink the LED. By default, there is an LED connected to Pin 13 on the board. So for testing we do not require any other peripherals. Start typing the following lines of code. The following code is in C language. Code: void setup(){     // What ever is written within these brackets are executed once. pinMode(13,

Hey guys! Lets start experimenting with the arduino. I have an arduino duemilanove. with the following parameters... ARDUINO Microcontroller : ATmega328 operating voltage :  5V Input voltage :  6-20 V Digital I/O pins :  14 Analog Input pins : 6              DC Current per I/O Pin : 40 mA DC Current for 3.3V Pin :  50 mA Flash Memory : 32 KB SRAM : 2 KB EEPROM :  1 KB ClockSpeed :  16 MHz First up blinking LED! Blinking LED is the basic and the first thing you should learn.First let us connect the Arduino to the computer. Then start the arduino IDE. if you do not have the IDE, then visit the Arduino Website and download it.when you open the arduino IDE you will see the following window. Arduino IDE Now go to tools, boards and then select the board you are using. I am using a Arduino duemilanove. Now go to tools, Serial port and select the port to which you have connected. If you dont know the port just select one port and upload the program. If you get an error then change the port un

Peltier module Peltier module is a device which uses the peltier effect to create a heat difference between the two sides of the device.In simple terms its like a heat pump. It takes the heat from one side (The side which becomes cold) and transfers it to the other side (the side which becomes Hot). These are very compact and efficient. A DC source should be connected to this module. The Peltier module I have, requires a 12 volts supply. They are available in a lot of power rating. The higher the power rating the higher the capacity to pump the heat from one side to another. As you can see the image it has two terminals, one is red for +12 Volts and and black for ground. I tried to connect a 12 volts lead acid battery but it was not providing sufficient amount of current. So I took an SMPS from my old computer and used the +12 volts supply. Advantages: They are compact. Small in size. The one I have is around 4cmx4cm. and it can easily freeze water. no refrigerant required. unlike con

Hey guys!  I have a Samsung galaxy S duos (GT-7562). I am traveler , hence  I tend to use GPS a lot which drains my mobile battery pretty fast. So I  wanted to build a portable charger for my mobile. I got a LM7805 voltage regulator and built a 5 V power supply. I connected it to a female USB port and tried to charge my mobile, but in vain. Then i took a SMPS from a spare computer in my workplace and connected the 5 V output to the female USB port and tried to charge my phone. Yet again my phone did not charge. I was puzzled, my   Raspberry Pi was working with both the chargers but not my mobile. So I  wondered whether Samsung engineers have utilized the same idea as apple. I  have an apple iPod 4G to charge apple products you have to connect the data pins to a certain potential, this is to prevent fake charging. So after a little research I found that the data pins must be shorted and the pins should be connected to +5 V  in series with a 33K resistor and connect it to ground with a 1

Raspberry Pi Model B The Raspberry Pi is a small desktop computer designed and developed by the Raspberry Pi foundation in UK. it comes in two models, Model A and model B. The one I have is a Model B. Model A: USB: Single USB connector Ethenet: No Memory: 256 Mb RAM chip: Broadcom BCM2835 SoC  CPU: 700 MHz ARM1176JZ-F. Can be overclocked to 1 GHz. Video: HDMI out / composite RCA Audio: 3.5mm Jack Storage: SD MMC SDIO Card slot OS: Linux Dimensions: 8.6cm x 5.4cm x 1.5cm Model B: USB:  Dual USB connector Ethenet:  Yes Memory:  512 Mb RAM chip:  Broadcom BCM2835 SoC  CPU:  700 MHz ARM1176JZ-F. Can be overclocked to 1 GHz. Video:  HDMI out / composite RCA Audio:  3.5mm Jack Storage:  SD MMC SDIO Card slot OS:  Linux Dimensions:  8.6cm x 5.4cm x 1.5cm