Keyestudio KS0077, Manual, Page: 22 / 142

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Sample Code
Since it is a simulation of traffic lights, the blinking time of each LED should be the same with
those in traffic lights system. In this program, we use Arduino delay () function to control delay
time, which is much simpler than C language.
//////////////////////////////////////////////////////////
int redled =10; // initialize digital pin 8.
int yellowled =7; // initialize digital pin 7.
int greenled =4; // initialize digital pin 4.
void setup()
{
pinMode(redled, OUTPUT);// set the pin with red LED as “output”
pinMode(yellowled, OUTPUT); // set the pin with yellow LED as “output”
pinMode(greenled, OUTPUT); // set the pin with green LED as “output”
}
void loop()
{
digitalWrite(greenled, HIGH);//// turn on green LED
delay(5000);// wait 5 seconds
digitalWrite(greenled, LOW); // turn off green LED
for(int i=0;i<3;i++)// blinks for 3 times
{
delay(500);// wait 0.5 second
digitalWrite(yellowled, HIGH);// turn on yellow LED
delay(500);// wait 0.5 second
digitalWrite(yellowled, LOW);// turn off yellow LED
}
delay(500);// wait 0.5 second
digitalWrite(redled, HIGH);// turn on red LED
delay(5000);// wait 5 second
digitalWrite(redled, LOW);// turn off red LED
}
//////////////////////////////////////////////////////////
Result
When the uploading process is completed, you can see traffic lights of your own design.
Note: this circuit design is very similar with the one in LED chasing effect.
The green light will be on for 5 seconds, and then off, followed by the yellow light blinking for 3
times, and then the red light is on for 5 seconds, repeatedly forming a cycle.
Experiment is now completed, thank you!