1. Traffic Light Controller
Presented To:
Sir. Waseem Nazar
H.O.D Electronics Dept.
Presented By:
M Tahaa EE106013
Usman Naseem EE305043
Sohaib Amar CH EE
M Zulfiqar Saeed BE107901

2. Traffic Light Controller Basic Functionality
Intersection of roads:
Highway (busy);
Country Road (not busy).
Want to give green light to highway as much as possible.
Want to give green to country road only when needed.
Want to give red to highway road only when car or pedestrian arrives.
Must always have at least one red light to avoid accidents.

3. System operation
Sensor on country road indicates when car’s on country road are waiting for green light.
Must obey required timings for green, yellow lights.
All operation is controlled by the clock.

4. Country Road
Sensor
Highway

5. Scenarios
If only Car or Car & Pedestrian approaches on Country Road & Highway respectively.
If only Pedestrian approaches on Highway.
Car Doesn’t Arrive at all.
Car Arrives after Highway Signal gets Yellow.
Car Arrives after Highway Signal gets Red.

6. If only Car or Car & Pedestrian approaches on Country Road & Highway respectively.

7. Country Road
Sensor
Highway

8. Sensor Checks for Vehicle on Country Road or Pedestrian on Highway
After max. 25 Seconds
Sensor Checks for Vehicle on Country Road or Pedestrian on Highway

9. Country Road
Sensor
Highway

10. Sensor Detects a Vehicle on Country Road

11. Country Road
Sensor
Highway

12. After 4 Seconds

13. Country Road
Sensor
Highway

14. Or as soon as Car or Pedestrian Crosses Highway
After max. 25 Seconds
Or as soon as Car or Pedestrian Crosses Highway

15. Country Road
Sensor
Highway

16. After 4 Seconds

17. Country Road
Sensor
Highway

18. Same case for Pedestrian.
At this stage it should be noted that if a car is still on Country Road even after the 25 Sec. Then it will have to wait for another 25 seconds till the Sensor detects it again and Stops the Highway Traffic !
Same case for Pedestrian.

19. 2. If only Pedestrian approaches on Highway.

20. Country Road
Sensor
Highway

21. Sensor Checks for Vehicle on Country Road or Pedestrian on Highway
After max. 25 Seconds
Sensor Checks for Vehicle on Country Road or Pedestrian on Highway

22. Country Road
Sensor
Highway

23. Sensor Detects a Pedestrian on Highway

24. Country Road
Sensor
Highway

25. During 4 Seconds If Car Doesn’t approach Country Road
If Car approach Country Road

26. Country Road
Sensor
Highway

27. During 15 Seconds If Car Still Doesn’t approach Country Road
If Car approaches Country Road

28. Or as soon as Pedestrian Crosses Highway
After max. 15 Seconds
Or as soon as Pedestrian Crosses Highway

29. Country Road
Sensor
Highway

30. After 4 Seconds

31. Country Road
Sensor
Highway

32. If Car approaches Country Road
During 4 Seconds
If Car approaches Country Road

33. Country Road
Sensor
Highway

34. Or as soon as Pedestrian and Car Crosses Highway
After max. 25 Seconds
Or as soon as Pedestrian and Car Crosses Highway

35. Country Road
Sensor
Highway

36. After 4 Seconds

37. Country Road
Sensor
Highway

38. During 15 Seconds
If Car approaches Country Road

39. Country Road
Sensor
Highway

40. Or as soon as Car or Pedestrian Crosses Highway
After max. 25 Seconds
Or as soon as Car or Pedestrian Crosses Highway

41. Country Road
Sensor
Highway

42. After 4 Seconds

43. Country Road
Sensor
Highway

44. State Diagram Of The Signals
Vehicle present on side street = Vs
Pedestrian present on Highway = PM
25 s timer (long timer) is on = TL
15 s timer (Pedest. timer) is on = TP
4 s timer (short timer) is on = TS
TL ( VS + + PM )
1st State 000
Main: Green
Side: Red TS
Main:Red Side:Green TS
7th State 110
Main: Yellow
Side: Red
Main:Red Side:Green
(TLVS ) or (TLVSPM)
(TL PM)
TP + PM
TPVS
2nd State 001
Main: Yellow
Side: Red
Main:Red Side:Red
6th State 101
Main: Red
Side: Red
Main: Green Side:Green
TSVS TS
TP PM TS TS TS
3rd State 010
Main: Red
Side: Green
5th State 100
Main: Yellow
Side: Red
Main:Green Side:Red
Main:Red Side:Green
4th State 011
Main: Red
Side: Yellow
(TL + (TL& (VS + PM))
TL& (VS + PM) TS
Main:Red Side:Red TS

45. The End