In this video, I teach the programming of the control of traffic lights in 4 streets by Logo.
So that by turning on the push button of I1, the green light will immediately turn on for 10 seconds on the first street.
And from the tenth second, the yellow light of the first street lights up for 3 seconds.
When the green light or the yellow light of the first street is on, the red light of the first street must be turned off.
On the second street, from the 13th second, the green light will be on for 8 seconds.
And from the 21st second, the yellow light of the second street lights up for 4 seconds.
When the green light or the yellow light of the second street is on, the red light of the second street must be turned off.
On the third street, from the twenty-fifth second, the green light turns on for 9 seconds.
And from the thirty-fourth second, the yellow light of the second street lights up for 2 seconds.
When the green light or the yellow light of the 3rd street is on, the red light of the 3rd street must be off.
On the fourth street, from the thirty-sixth second, the green light turns on for 7 seconds.
And from the 43rd second, the yellow light of the 4th street lights up for 5 seconds.
When the green light or the yellow light of the 4th street is on, the red light of the 4th street should be turned off.
This cycle of 48 seconds is repeated.
In the first step, programming is done without considering the red lights, by the "Edge triggered wiping relay" function.
For each of the green or yellow lights, an "Edge triggered wiping relay" function is required.
In this timer, the starting time of the output and the duration of that output are set.
In the second step, I use a "Nor" gate for each of the red lights.
The reason is that when the green light or yellow light of a street is on, the red light of that street must be turned off.
One cycle of this traffic light is the total duration of green and yellow lights. which is equal to 48 seconds.
To get the duration of the red light of each street, I subtract the total duration of the green and yellow lights of that street from 48 seconds.
Therefore, the duration of the red light on the first street is 35 seconds, on the second and fourth streets, 36 seconds, and on the third street, 37 seconds.
In the third step, to repeat this cycle, I put a "Nand Edge" function.
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