3. Our aim is to make an automatic robot that can follow a white lined path placed over a black background. If the robot goes out of track then it senses the black region and returns to the white line.

4. The robot consists of 2 light detecting sensors paired with led s. We know that white color reflects the light very well and the black surface doesn’t reflect any light. The light emitted by the led s is reflected is reflected back to the light sensors and the robot moves forward. If the sensors come to the black region no light is reflected from the led s so the robot stops immediately.

5. IC7805 REGULATOR (9V-5V) LM324N COMPARATOR ULN2003 AMPLIFIER LDR (LIGHT SENSORS) LED POTENTIOMETER 10K Ώ 4 PIN CONNECTOR CARBON RESISTANCE OF 10K Ώ CARBON RESISTANCE OF 100 Ώ

7. This technology can be used for preventing an automobile from getting on to the off road by controlling the electronic breaks present in the vehicles preventing it from a great accident. This circuit should be placed in the middle of the breaks and supply. The only investment is to paint the roads with white near the medians and at extreme left of the roads.

8. So if a car get on to this white region the breaks gets operated preventing a great accident The only defect is this technology cannot be implemented during rain as the black region also starts reflecting light. This technology is the key for future generation where cars don’t have steering wheel and only has accelerators and breaks.

10. WIRELESS ELECTRIC POWER TRANSMISSION MAGNETIC INDUCTION WIRELESS TRANSMISSION OF CURRENT IS BASED ON THE ELECTRO MAGNETIC INDUCTION.

11. Nikola Tesla was the first person to work on this concept. This is based on the Faradays law of electromagnetic induction. The faraday ’ s law states that when a coil of wire cut a magnetic field or when the magnetic field cuts the coil of wire, current is induced in the wire. INTRODUCTION

12. In the case of a D.C current the magnetic field created is constant and so the magnetic field should be interrupted as to make a difference in potential in the coil. Whereas in A.C current the magnetic field generated is varying and this varying magnetic field creates an e.m.f in the coil without any movement in the coil. Hence A.C current can be used for the transmission of the current. With A.C, a magnetic field is generated and is used to transmit electricity without any physical contact or connecting each other with wires.

13. COMPONENTS Resistor (  ) Capacitor Transistor L.E.D Copper Coil Connecting wire

14. The D.C current is first converted to A.C current. The converted current is then passed through a coil (primary coil) of wire to create a varying magnetic field. So when a coil of copper wire is brought on the track of this magnetic field the copper coil (secondary coil) gains a potential difference. And finally the A.C current is used in the circuit to light up an L.E.D. The A.C current is a varying current which changes its polarities. But it will not make any difference as the L.E.D blinks so fast that we would not be able to identify the difference and we may get a constant glow. Where as in the case a D.C current the current flowing is constant and the bulb or an L.E.D will glow constantly.

15. µ -permeability of free space

17. In the case of a straight wire the direction of magnetic lines of force can be found out by placing the thumb of right hand along the direction of current. The direction of magnetic lines is along the direction of our other fingers. But in the case of a coil of wire it contains n- loops. In the case of a loop it contains minute straight lines. So the resultant direction is different in the case of a loop. The direction of magnetic lines of force in the case of a loop can be determined by placing all the fingers except the thumb along the direction of current and the thumb must be kept perpendicular to the other fingers as shown in the figure. Then the thumb gives the directions of the magnetic lines of force.

19.  Generating power by placing satellites with giant solar arrays in Geosynchronous Earth Orbit and transmitting the power as microwaves to the earth known as Solar Power Satellites (SPS) is the largest application of WPT. Another application of WPT is moving targets such as fuel free airplanes, fuel free electric vehicles, moving robots and fuel free rockets. The other applications of WPT are Ubiquitous Power Source (or) Wireless Power Source, Wireless sensors and RF Power Adaptive Rectifying Circuits (PARC).

20. This technology is being used in charging mobile phones. This can be used in connecting networks which are situated in places that are impossible to connect to.

24. TThis is a hand testing game to see how shaky one’s hand is. TThe principle of the game is very simple !. TThere is a maze over which one has to move a circular loop.  If the hand is shaky then loop touches the maze and there is a sound showing that you have failed in the game. IIf the hand is not shaky then one can bring the loop from the start to end of the maze

25. TThe circuit consist of a led, 470Ω resistor, a 9V battery, a switch and a buzzer. TThe positive of the battery is connected to the led ‘s anode through a c cc current limiting resistor. TThe negative of the battery is connected to the maze. TThe cathode of the led is connected to the loop through a switch. AA buzzer is also connected to make the game more interesting. WWhenever the loop touches the maze the circuit is completed and the led and buzzer gets supply at the same time and the user loses his chance.

28.  Ohms law states that the potential difference across two points is directly proportional to the current flowing through the two points or in other words, the ratio of the voltage to current is a constant.  That is when the resistance in between the two points increases the current flowing through the two points decreases to maintain the same potential difference.  Similarly when the resistance in between the two points decreases the current flowing through the two points increases to maintain the same potential difference.

29.  This is the demonstration of the Ohms law.  A led and a buzzer are connected to a variable resistor.  Changing the resistance changes the current passing through the led and buzzer.  The circuit consists of a led, pot, buzzer, a 470 Ω resistor, a variable resistor – 10 K Ω pot and a buzzer.  The Ohms law is demonstrated by varying the potentiometer.

30. WWhen the resistance of the pot is at 0K the resistance is very low and therefore maximum current flows in the circuit and the led gives its maximum light and buzzer its maximum sound.  When the resistance of the pot is at 10K the resistance is very high and therefore a very low current flows in the circuit and the led gives its minimum light and buzzer its minimum sound.  I In an intermediate position the led glows according to the available current.

31.  This can be shown by varying the pot in one direction and the led dims gradually and in the other direction it brightens up gradually. Similarly the buzzer sound is also increased in one direction and decreased in the other direction.  This is a simple and effective demonstration of Ohms law which every one can understand easily.

34. Infra red sensor is a circuit which enables us to detect infra red leakage in nuclear power plants. Here is a basic model which can detect ir radiations even if the source is quite far. The circuit consists of an stop 1738,ne555,led and some wires and capacitors of value less than 1uf.