Hi, I want to make a LED blink project without delay() LIKE A POLICE STROBE LIGHT. The project is like
LED 13 ON DELAY(50)
LED 13 OFF DELAY(50)
LED 13 ON DELAY(50)
LED 13 OFF
DELAY(1000)
But the LED only blink for 1000 ms...
Pls solution.
int ledPin = 13; // the LED pin connected to NANO
unsigned long OnTime = 50; // milliseconds of on-time
unsigned long noOfTime = 1000; //milliseconds of time for blinker
unsigned long previousMillis = 0; // will store last time LED was updated
bool ledState = LOW;
unsigned long previousMillis1 = 0; //for blinker timing
void setup()
{
pinMode(ledPin, OUTPUT);
}
void loop()
{
if ( ( millis() - previousMillis1 >= noOfTime))
{
blinker();
previousMillis1 = millis();
}
}
void blinker() {
if (ledState == LOW) ledState = HIGH;
else ledState = LOW;
{
digitalWrite(ledPin, ledState); // Update the actual LED
}
previousMillis = millis();
}
An alternative way to do this would be to update a counter every 50ms. When the counter reaches 20, set it back to zero. If the counter is 0 or 2, switch on the led, else switch off the led.
{
// Class Member Variables
// These are initialized at startup
int ledPin; // the number of the LED pin
long OnTime; // milliseconds of on-time
long OffTime; // milliseconds of off-time
// These maintain the current state
int ledState; // ledState used to set the LED
unsigned long previousMillis; // will store last time LED was updated
// Constructor - creates a Flasher
// and initializes the member variables and state
public:
Flasher(int pin, long on, long off)
{
ledPin = pin;
pinMode(ledPin, OUTPUT);
OnTime = on;
OffTime = off;
ledState = LOW;
previousMillis = 0;
}
void Update()
{
// check to see if it's time to change the state of the LED
unsigned long currentMillis = millis();
if((ledState == HIGH) && (currentMillis - previousMillis >= OnTime))
{
ledState = LOW; // Turn it off
previousMillis = currentMillis; // Remember the time
digitalWrite(ledPin, ledState); // Update the actual LED
}
else if ((ledState == LOW) && (currentMillis - previousMillis >= OffTime))
{
ledState = HIGH; // turn it on
previousMillis = currentMillis; // Remember the time
digitalWrite(ledPin, ledState); // Update the actual LED
}
}
};
Flasher led1(13, 50, 1000);
void setup()
{
}
void loop()
{
led1.Update();
}
But i need double blink or tripple blink etc. Now the led blink for 50ms and off for 1000ms as per the programme
Check if the following sketch serves your purpose. The sketch makes 4 blinks; where the first 31/2 blinks are with 1000 ms on-period and off-period. The last off-time of the last blink is 3000 ms. This sketch uses "Blink Without Delay" approach.
unsigned long previousMillis = 0; // will store last time LED was updated
long interval = 1000; // interval at which to blink (milliseconds)
const int ledPin = LED_BUILTIN;// the number of the LED pin
int ledState = LOW; // ledState used to set the LED
byte counter = 0;
void setup()
{
pinMode(ledPin, OUTPUT);
}
void loop()
{
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval)
{
if(interval == 3000)
{
interval = 1000;
counter = 0;
}
previousMillis = currentMillis;
if (ledState == LOW)
{
ledState = HIGH; //ON
}
else
{
ledState = LOW; //OFF
}
counter++;
digitalWrite(ledPin, ledState);
if (counter == 4)
{
interval = 3000;
}
}
}
Not that it really matters here, but just to keep in mind, when you update previousMillis by setting it to either currentMillis or millis() the time will drift and be longer than you expect. To keep it accurate, do this instead:
previousMillis += OnTime;
That keeps the long term timing accurate no matter what you do in code.
You have wanted:
ON for 50 ms (in my sketch 1000 ms)
OFF for 50 ms (in my sketch 1000 ms)
ON for 50 ms (in my sketch 1000 ms)
and then OFF for 1000 ms (in my sketch 3000 ms)
and then repeats
counter == 10 means the Led has blinked 41/2 times; there remains the last off-time of 3000 ms (in your case 1000 ms). I have checked my sketch, and it blinks exactly for five times with last off-time for 3000 ms.
Imo, PaulRB's method of counting in 50ms intervals and not changing the interval but turning the led off at count 0 or 2 and otherwise on is a more elegant way.
If you are a beginner, then why have you introduced object based codes in Post-7? Have you copied it from somewhere? I have preapred my skecth of Post-9 based on the Arduino's example of "Blink Without Delay".
// https://forum.arduino.cc/t/double-blink-and-delay-for-1000-ms-without-delay/904431
// implements counter as suggested by PaulRB
/*
BASED ON Blink without Delay
Turns on and off a light emitting diode (LED) connected to a digital pin,
without using the delay() function. This means that other code can run at the
same time without being interrupted by the LED code.
The circuit:
- Use the onboard LED.
- Note: Most Arduinos have an on-board LED you can control. On the UNO, MEGA
and ZERO it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN
is set to the correct LED pin independent of which board is used.
If you want to know what pin the on-board LED is connected to on your
Arduino model, check the Technical Specs of your board at:
https://www.arduino.cc/en/Main/Products
created 2005
by David A. Mellis
modified 8 Feb 2010
by Paul Stoffregen
modified 11 Nov 2013
by Scott Fitzgerald
modified 9 Jan 2017
by Arturo Guadalupi
This example code is in the public domain.
http://www.arduino.cc/en/Tutorial/BlinkWithoutDelay
*/
// constants won't change. Used here to set a pin number:
const int ledPin = LED_BUILTIN;// the number of the LED pin
// Variables will change:
//int ledState = LOW; // ledState used to set the LED
// Generally, you should use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis = 0; // will store last time LED was updated
// constants won't change:
const long interval = 50; // interval at which to blink (milliseconds)
byte counter = 0;
void setup() {
// set the digital pin as output:
pinMode(ledPin, OUTPUT);
}
void loop() {
// here is where you'd put code that needs to be running all the time.
// check to see if it's time to blink the LED; that is, if the difference
// between the current time and last time you blinked the LED is bigger than
// the interval at which you want to blink the LED.
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval) {
// save the last time you blinked the LED
previousMillis = currentMillis;
// turn led on at count 0 or 2, otherwise off
if (counter == 0 || counter == 2)
digitalWrite(ledPin, HIGH);
else
digitalWrite(ledPin, LOW);
counter++;
//reset counter
if (counter == 20) counter = 0;
}
}
