Writing the Fade Code with analogWrite | Task 3

How 'for' loops work.

Imagine you have a box of chocolates, and you want to enjoy them one by one until the box is empty. A ‘for’ loop in the C programming language works a bit like that.

In a ‘for’ loop, you have three important components:

• Initialization: Think of this as deciding how many chocolates you have and where to start.
• Condition: A rule to decide when to stop eating chocolates.
• Update: After each chocolate, move on to the next one.

Here’s how it looks in C code:

        for (int cookie = 1; cookie <= 10; cookie++) {
          Serial.println("Enjoying cookie number " + String(cookie));
        }
        

Using a for Loop to Control Brightness

To gradually change the brightness of an LED, we use a for loop to repeat small steps over time.

Below is the full code to make an LED fade in and out using Pulse Width Modulation (PWM). The LED will gradually brighten, then dim in a loop.

        
// Lesson 3: Fade LED using PWM

int ledPin = 5; // must be a PWM-capable pin

void setup() {
  pinMode(ledPin, OUTPUT); // Set the LED pin as an output
}

void loop() {
  // Fade from off to full brightness
  for (int brightness = 0; brightness <= 255; brightness++) {
    analogWrite(ledPin, brightness); // Set brightness level
    delay(10); // Pause for smooth transition
  }

  // Fade from full brightness to off
  for (int brightness = 255; brightness >= 0; brightness--) {
    analogWrite(ledPin, brightness); // Set brightness level
    delay(10); // Pause for smooth transition
  }
}