The intersection junction of a railway and a road. The flashing light and warning bell are to be turned on when a train enters either from Area 1 or Area 3; and turn off when a train leaves the intersection. The flashing light and warning bell will turn on for 5 seconds and 3 seconds respectively when the train is in Area 1 or Area 3. Three signals P1, P2 and P3 are generated when a train is in Area 1, 2 and 3 respectively.
Hints:
(a) Your circuit should have 5 outputs, 3 signals for Area 1, Area 2 and Area 3. Use LEDs to simulate as outputs.
(b) The railway-crossing indicator has 4 states: No train approaching, Train approaching, Train at intersection junction and Train left the intersection junction.
(c) Use counters to keep track of time for the flashing light and warning bell signals.
(d) Use LEDs to simulate P1, P2 and P3 signals.
(e) Use switches to simulate the presence of train in respective area.
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