Manual and Automatic Traffic Lights

Now... let's start!

LEDs light faded to on or off, through the pot, using PWM (Pulse Width Modulation).

"oh oh! sorry, it's late; my dog just called me on phone, have to bring house to piss, my wife's unattended..."

Stop! We'll use PWM without knowing anything about it.

Just learn that it's a technique to output analog-continuous values with digital-discontinuous ones.

If you mounted the circuit as in first picture, disconnect every wire from Arduino; now connect it only to pc.

 

 

 

Open Arduino IDE, tool to program it; write, compile the following code and upload to the board.

const int analogInPin = A0;  // Analog input pin that the potentiometer (wiper)
                             // is attached to

const int analogOutPin9 = 9;   // Check your arduino board
const int analogOutPin10 = 10; // among digital pins
const int analogOutPin11 = 11; // you'll find someone marked with PWM

int sensorValue = 0;        // value read from the pot
int outputValue = 0;        // value output to the PWM (analog out)

void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(9600);
  // every command starting with "Serial" means a communication with a serial
  // monitor, if arduino is connected to pc you can use the internal one
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);
  // map it to the range of the analog out:
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  // Arduino can generate PWM on a scale from 0 to 255; so that map function
  // returns value proportional to the input, that goes from 0 to 1023

 analogWrite(analogOutPin9, outputValue);
 Serial.print("sensor = " );
 Serial.print(sensorValue);
 Serial.print("\t output 9 = ");
 Serial.println(outputValue);

 analogWrite(analogOutPin10, outputValue);
 Serial.print("sensor = " );
 Serial.print(sensorValue);
 Serial.print("\t output 10 = ");
 Serial.println(outputValue);

 analogWrite(analogOutPin11, outputValue);
 Serial.print("sensor = " );
 Serial.print(sensorValue);
 Serial.print("\t output 11 = ");
 Serial.println(outputValue); 

 delay(3); // 3 milliseconds every loop
}

We now can fade LEDs all together. Watch the video below.