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The countdown traffic lights technical parameters
- Nov 18, 2018 -

The countdown traffic lights technical parameters

(1) light intensity: 4000 CD or higher
(2) working voltage: 12 v
(3) power: 5 w or less
(4) light source life: 100000 hours or more
(5) heat resistance: - 40 ℃ ~ + 75 ℃
(6) visual Angle: 300 or more
(7) the visual distance: 400 mm light 400 m or more
(8) hot and humid performance: air relative humidity 5% ~ 95%
(9) : protection grade acuity IP43
Insulation resistance (10) : more than 10 m Ω
(11) dust: GB14887-2003 standard
(12) vibration resistance: GB14887-2003 standard
(13) of: 145 km/h

Introduction of the principle
The traffic light is an important and indispensable tool in the urban traffic, is the important guarantee of urban traffic order. This example is to implement a common cross road lamp function. Readers by studying the traffic light controller, can achieve a more complete traffic lights. Such as real-time configuration of various light time, manual control each lamp status, etc.
An intersection traffic generally divided into two directions, each direction has red, green and yellow light, each direction also have left turn lights, so I have four lights each direction.
The traffic light is designed for the state of each lamp countdown digital tube display. Can be set for each lamp state of an initial value, the lamp after state changes, beginning in accordance with the countdown to the initial value. After the countdown to zero, the state of the lights will change to the next state.
It is worth noting that the traffic light the lamp in the direction of the two states are related. That is to say, the influence of the state of each direction of the light with the light in the direction of another state, it can coordinate the two directions of traffic. If the lamp is independent changes in each direction, then the traffic light, there is no significance.

Implementation method
As shown in table 1 are the two directions (hypothesis for A, B) the state of the light of the corresponding situation.
Table 1 traffic light two directions corresponding table lamp status
Direction of A
The direction B
Red light
Yellow light and green light
Straight green light
Red light
Yellow lights
Red light
Left turn signal
Red light
In an actual traffic system, the way of the change of the green light, turn left, the green light and red light should have yellow light as a buffer between, to ensure the safety of transportation.
So if we assume that the direction of A yellow lights lasted 5 s, 40 s, the straight green lights lasts left turn signal lights for 15 s of time, the direction for the red lights lasts B (straight green + + left green + yellow light yellow light) the consumed time, A total of 65 s.
Also assume direction B yellow lights lasted 5 s, straight green light time lasts 30 s, left turn signal lights for 15 s of time, the direction for the red lights lasts B (straight green + + left green + yellow light yellow light), a total of 55 s.

Author:Bunny Sun