• Home
  • Archive
  • Tools
  • Contact Us

The Customize Windows

Technology Journal

  • Cloud Computing
  • Computer
  • Digital Photography
  • Windows 7
  • Archive
  • Cloud Computing
  • Virtualization
  • Computer and Internet
  • Digital Photography
  • Android
  • Sysadmin
  • Electronics
  • Big Data
  • Virtualization
  • Downloads
  • Web Development
  • Apple
  • Android
Advertisement
You are here:Home » Arduino : Independently Blink Multiple LED

By Abhishek Ghosh January 18, 2021 7:03 am Updated on January 18, 2021

Arduino : Independently Blink Multiple LED

Advertisement

A practical question which comes up every day is how to blink two LEDs at different rates? That simply means an independent control on each LED. That small wish is a big jump to visual animation. In real life, the multi-coloured Christmas lights (aka Dewali lights) blinks in that fashion to give us a great feel. Problem to most of the beginners is with the usual “blink” tutorial program :

Vim
1
2
3
4
5
6
7
8
9
10
11
12
void setup()
  {                
  pinMode(13, OUTPUT);    
  }
 
void loop()
  {
  digitalWrite(13, HIGH);   // set the LED on
  delay(1000);              // wait for a second
  digitalWrite(13, LOW);    // set the LED off
  delay(1000);              // wait for a second
  }

This program works fine to blink one LED. But to blink two LEDs, unless you want to blink them both at once or one after the other, you lack control. If you want to blink the two LEDs at different rates such as once a second for LED 1 and twice a second for LED 2 then the delay() function is not what you are looking for. That is, you can’t do anything else until the one task at hand is over. That is called “blocking”. To resolve this problem of “blocking”, there are many solutions, more or less difficult:

  1. using millis()
  2. using a table-driven approach
  3. using a Finite-State Machine logic

By using a clever trick with milis(), we will not need to call delay() for one LED:

Advertisement

---

Vim
1
2
3
4
5
6
7
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}
 
void loop() {
  digitalWrite(LED_BUILTIN, (millis() / 1000) % 2);
}

Arduino’s millis() function returns the number of milliseconds the program has started running. We divide this value by 1000 and get the number of seconds passed. Then we take the number of seconds and divide it by two using the modulus (%) operator. This calculation returns 0 for even numbers and 1 for odd numbers. This approach is no longer blocking – we can perform another task within the loop.

Arduino Independently Blink Multiple LED

Dan Hoover’s article “Understanding Blink Without Delay” has an example with 3 LEDs using millis() :

Vim
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
int red = 2;
int intervalRed = 1000; //how long to delay in millis
unsigned long previousRed = 0;
int redState = LOW;
 
int blue = 3;
int intervalBlue = 2500; //how long to delay in millis
unsigned long previousBlue = 0;
int blueState = LOW;
 
int green = 4;
int intervalGreen = 5000; //how long to delay in millis
unsigned long previousGreen = 0;
int greenState = LOW;
 
void setup() {
  Serial.begin(9600);
  pinMode(red, OUTPUT);
  pinMode(blue, OUTPUT);
  pinMode(green, OUTPUT);
}
 
void checkRed() {
  unsigned long currentMillis = millis();
 
  if (currentMillis - previousRed >= intervalRed) {
    //save this reading!
    previousRed = currentMillis;
 
    //figure out if you should turn the LED on or off
    if (redState == LOW) {
      redState = HIGH;
    } else {
      redState = LOW;
    }
    digitalWrite(red, redState);
  }
}
 
void checkGreen() {
  unsigned long currentMillis = millis();
 
  if (currentMillis - previousGreen >= intervalGreen) {
    //save this reading!
    previousGreen = currentMillis;
 
    //figure out if you should turn the LED on or off
    if (greenState == LOW) {
      greenState = HIGH;
    } else {
      greenState = LOW;
    }
    digitalWrite(green, greenState);
  }
}
 
void checkBlue() {
  unsigned long currentMillis = millis();
 
  if (currentMillis - previousBlue >= intervalBlue) {
    //save this reading!
    previousBlue = currentMillis;
 
    //figure out if you should turn the LED on or off
    if (blueState == LOW) {
      blueState = HIGH;
    } else {
      blueState = LOW;
    }
    digitalWrite(blue, blueState);
  }
}
 
 
void loop() {
  checkRed();
  checkGreen();
  checkBlue();
}

I provided the above example simply because on this webpage you’ll get the emulation against the above code (click “Run the code” button and watch the 3 LEDs above the video). Using millis() is not super-easy but we use milis() in lot of sketches for Arduino and ESP32.

Tagged With arduino blink with two led , arduino multiple LEDs with different delays , arduino with multiple led , https://thecustomizewindows com/2021/01/arduino-independently-blink-multiple-led/ , millis multi function led
Facebook Twitter Pinterest

Abhishek Ghosh

About Abhishek Ghosh

Abhishek Ghosh is a Businessman, Surgeon, Author and Blogger. You can keep touch with him on Twitter - @AbhishekCTRL.

Here’s what we’ve got for you which might like :

Articles Related to Arduino : Independently Blink Multiple LED

  • Arduino and LED Bar Display : Circuit Diagram, Code

    Here is a Guide Explaining the Basics, Circuit Diagram, Code on Arduino and LED Bar Display. LED Bar Display is Actually Like Multiple LED.

  • Arduino Blink LED With Pushbutton Control to Turn ON and Off

    Arduino Blink LED With Pushbutton Control to Turn ON and Off is Few Steps Higher Than Basic Example. There is Matter of Repeat Checking by Microcontroller.

  • How to Control Multiple Relays With Single Arduino ESP32?

    Before How to Control Multiple Relays With Single Arduino ESP32 Testing, You Need to Learn How to Create Multiple MQTT Channels & Fetch Data.

  • Arduino : Blink Two LEDs Alternatively

    Common Example of Arduino is To One LED. We Can Make Arduino To Blink Two LEDs Alternatively in Various Ways of Coding.

performing a search on this website can help you. Also, we have YouTube Videos.

Take The Conversation Further ...

We'd love to know your thoughts on this article.
Meet the Author over on Twitter to join the conversation right now!

If you want to Advertise on our Article or want a Sponsored Article, you are invited to Contact us.

Contact Us

Subscribe To Our Free Newsletter

Get new posts by email:

Please Confirm the Subscription When Approval Email Will Arrive in Your Email Inbox as Second Step.

Search this website…

 

Popular Articles

Our Homepage is best place to find popular articles!

Here Are Some Good to Read Articles :

  • Cloud Computing Service Models
  • What is Cloud Computing?
  • Cloud Computing and Social Networks in Mobile Space
  • ARM Processor Architecture
  • What Camera Mode to Choose
  • Indispensable MySQL queries for custom fields in WordPress
  • Windows 7 Speech Recognition Scripting Related Tutorials

Social Networks

  • Pinterest (24.3K Followers)
  • Twitter (5.8k Followers)
  • Facebook (5.7k Followers)
  • LinkedIn (3.7k Followers)
  • YouTube (1.3k Followers)
  • GitHub (Repository)
  • GitHub (Gists)
Looking to publish sponsored article on our website?

Contact us

Recent Posts

  • Affordable Earphone/IEM for Audiophiles: HiFiMan RE-400 WaterlineOctober 2, 2023
  • What is Hardware Security Module (HSM)September 30, 2023
  • Transducer Technologies of HeadphonesSeptember 28, 2023
  • What is Analog-to-Digital Converter (ADC)September 27, 2023
  • Comparison of Tube Amplifiers and SemiconductorsSeptember 26, 2023
PC users can consult Corrine Chorney for Security.

Want to know more about us?

Read Notability and Mentions & Our Setup.

Copyright © 2023 - The Customize Windows | dESIGNed by The Customize Windows

Copyright  · Privacy Policy  · Advertising Policy  · Terms of Service  · Refund Policy