Timer-Based LED Blinker Using Arduino

The objective of this project is to create a Timer-Based LED Blinker using Arduino. By using the millis() function, we will create a non-blocking code that controls the blinking of an LED without the use of the delay() function, allowing other code to run simultaneously.

Fundamental Programming Concepts

• Timers (millis()): Tracks time since the program started, allowing for timed actions without blocking the program.
• Digital Output (digitalWrite()): Sends signals to control the LED by turning it on or off.
• Non-Blocking Code: Ensures that the program doesn’t pause while waiting for events like blinking, enabling multitasking.

Requirement Components

To complete this timer-based LED blinker using Arduino project, you will need:

• Arduino Uno Board
• LED
• 220Ω Resistor
• Breadboard
• Jumper Wires
• USB Cable (for connecting Arduino to your computer)

Circuit Diagram

Circuit Connection

How to Connect the Circuit

1. LED: Connect the anode (longer leg) of the LED to Pin 13 on the Arduino and the cathode to GND using a 220Ω resistor.
2. Power and Ground: Ensure the breadboard is connected to the Arduino’s 5V and GND pins for a stable power supply.

Explanation of Circuit

• The LED is connected to Pin 13 on the Arduino, which allows the board to control the blinking using digitalWrite().
• The millis() function will track the time elapsed since the Arduino was powered on and control when the LED should turn on or off.

Programming Section for Timer-Based LED Blinker Using Arduino

Arduino Syntax

Arduino Code:

Here’s the Arduino code to create a timer-based LED blinker using millis():

const int ledPin = 13;    // Pin connected to the LED
unsigned long previousMillis = 0;  // Store the last time the LED was updated
const long interval = 1000;  // Interval for blinking (1 second)
void setup() {
  pinMode(ledPin, OUTPUT);  // Set the LED pin as an output
}
void loop() {
  unsigned long currentMillis = millis();  // Get the current time
  // Check if the time interval has passed
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;  // Save the current time as the last time
    // Toggle the LED state
    if (digitalRead(ledPin) == LOW) {
      digitalWrite(ledPin, HIGH);  // Turn the LED on
    } else {
      digitalWrite(ledPin, LOW);   // Turn the LED off
    }
  }
}

Steps to Upload Code:

1. Connect your Arduino to your computer using a USB cable.
2. Open the Arduino IDE and select the correct Board and Port.
3. Copy and paste the provided code into a new sketch.
4. Click the Upload button to transfer the code to your Arduino.
5. Watch the LED blink on and off at 1-second intervals using the millis() timer.

Check Output

Once the code is uploaded, the LED connected to Pin 13 should blink at 1-second intervals. The millis() function will ensure that the code is non-blocking, allowing other processes to run simultaneously if needed.

Troubleshooting Tips

• LED not blinking? Double-check the LED’s connections to ensure it is connected correctly to Pin 13 and GND.
• No output? Verify that the code is uploaded correctly and that the Arduino is powered on.
• Flickering LED? Ensure the time interval and wiring are correct. You can adjust the interval by modifying the interval variable in the code.

Further Exploration

• Multiple LEDs: Add more LEDs with different intervals and control them using millis() to create complex blink patterns.
• Variable Blink Rate: Use a potentiometer to control the blink rate dynamically by adjusting the interval based on the potentiometer’s analog input.
• LCD Display: Display the elapsed time on an LCD along with the blinking LED.

Note

This project introduces the concept of using timers (millis()) to create a non-blocking LED blinker. Unlike delay(), which halts the program, millis() allows multitasking by keeping the program running while still tracking the time.

FAQ

Q1: What is the difference between delay() and millis()?
delay() pauses the entire program for a specified time, while millis() continues to run the program while tracking time, allowing you to perform other tasks in the background.

Q2: How does millis() work in this project?
The millis() function returns the time elapsed since the program started. By comparing the current time to the last time the LED state was updated, you can create a timed blinking effect without pausing the program.

Q3: Can I change the blink rate?
Yes, you can adjust the blink rate by changing the interval variable in the code. For example, changing the interval to 500 will make the LED blink every 0.5 seconds.

Q4: Can I control multiple LEDs using millis()?
Yes, you can control multiple LEDs by creating separate millis() intervals for each LED and toggling them independently.

Q5: Why is it important to use non-blocking code?
Non-blocking code ensures that your program can perform multiple tasks simultaneously. It is crucial for more advanced projects where timing and multitasking are needed.