Applying The LED System instead Of The RFID System In Transportation Toll

1. Saudi Arabia College of Engineering King Saud University Electrical Engineering Department Applying the LED System instead of the RFID system in transportation’s toll. EE-411 Optoelectronic Systems and Devices 2009-2010 (2nd Semester) Dr. HabibFathallah Dr. NacerDebbar By: Ahmad Hani Ismail –42710173 Mohammed Al-Masoudy– 425113782

3. Introduction

5. Its purpose is not to effect impact to traffic flow.

6. It allows vehicles to move freely through the tolling point at highway speeds without stopping.

8. It operates with no battery or moving parts and must not be removed from the windshield without damaging the tag.

9. this tag consist of a small ship inside which appear in black.

10. This ship is how the system identify each vehicle passing through.

14. Diode.

15. transistor (black, with three leads).

16. resonator (yellow).

17. two resistors (green)

18. a capacitor (dark blue

19. resistor (green)

22. 1.2.1.1 Diode in the LED

23. 1.2.1.1 Diode in the LED

24. 1.2.3 LED As Sensors A LED light sensor is a Light-Emitting Diode used as a photodiode, But it is biased in reverse voltage, and it work as current source. (look at Figure down)

25. Comparison between RFID system and LED system 1.2.4

27. Distance 2.1.1 Distance between LED transmitter and Photo-Receiver was assumedto be 5 meters. 5 m.

28. Wavelength, Frequency and Photon Energy 2.1.2 We studied that we can determine all of the wavelength, frequency and photon energy by a given Figure to be determined and known as standards. (Look at the Figure) From the figure above we find that Infrared has a frequency of , wavelength of and energy of .

29. Divergence & Intensity 2.1.3 Wavefronts of a Gaussian light beam. Light intensity across beam cross section. (c) Light irradiance (intensity) vs. adial distance r from beam axis (z).

31. Slowly divergent beam and rays

32. Finite extent light source 2wo

33. 2wois called the (waist of the beam) or (Spot Size)

34. wois the waist radius of the beam.

36. Divergence & Intensity 2.1.3 By Fethagorse we find (X) which is in the cross section of the beam at receiving. . . X = 3.18 cm (Cross section area of the beam at receiver in at distance 5m )= X * 2 = 3.18cm*2 =6.36 cm .

37. Divergence & Intensity 2.1.3 Due to the divergence we found, we come up with some designing issue like the ability of detecting the LED Beam even in the worst cases of weather or temperature. We started a designing the photo-receiver by designing a system with one LED Photo-receiver as shown in Figure below.

38. Divergence & Intensity 2.1.3 After the previous design we considered the divergence and the attenuation of the air medium, We suggested that we better put many photo-receiver instead of one so it can receive the beam in different photo-receivers then it can be gathered in the end as one code.

39. Divergence & Intensity 2.1.3 And then we thought of developing the system to make it work in more effective way to receive all beams heading toward all directions by creating conditions most suited. We applied a Photo-receiver in the right and the left side of thePassageway, also we used a kind of medium which is suitable to reflect any beam heading toward the two sides of the passageway so we applied a surface of medium such as mirror on the two sides of the passage way. As in Figure.

40. LED driver circuit. 2.2 This is the components and its details that can be determined due to the parameters and the calculations, the circuit is as shown in Figure: -For the previous circuit the manufacture has determined that: Minimum input voltage for 1 LED : 5VAC The evaluation board is designed to display the full functionality as a LED driver to drive 1W at 12Vac input. Based on this circuit, there are nine different configurations with different input voltages and output power levels that could be derived by making minor components changes to the evaluation board.

41. LED Photo-receiver drive circuit 2.3 This is an example of the photo-receiver drive circuit that takes advantage of the photo-voltaic voltage of an ordinary LED. The LED voltage is buffered by a junction FET transistor and then applied to the inverting input of an op-amp with a gain of about 20. This produces a change of about 5 volts.

44. Light Emitting Diode (LED) consists of a chip of semiconducting material doped with impurities to create a p-n junction. The principle of our new optoelectronic system has the same principle of the applications of the LED system in Television remote control. Each vehicle will have its own coding just like the coding in the television remote control. We are studying the system to develop a successful LED optoelectronic system so it can be used instead of the RFID system in Toll gates for transportation. We design the system of the LED regarding to our calculations of distance, wavelength, divergence, frequency, and power. Due to the distance, we can determine the power needed with regard to that the photo-receiver sensor must have properties that allow receiving a determined power. Conclusion:

45. Development: We Can develop our LED System and apply a small Solar-cell part instead of car Battery. That would : 1- Save power in car’s Battery 2- Make LED life longer