***Arduino Ethernet Shield Port Forwarding Router

 https://randomnerdtutorials.com/arduino-ethernet-web-server-with-relay/

Arduino Milis and Micros without Delay

 

 

https://www.youtube.com/watch?v=rUtDfadf8Jk

 

 

https://robojax.com/learn/arduino/?vid=robojax_millis_blink 

 /*
 * LED Blink with millis() with different time interval of ON and OFF time
 * Written by Ahmad Shamshiri for Robojax.com and Robojax YouTube channel
 * written on Aug 05, 2019 in Ajax, Ontario, Canada at 12:41
 * Watch video instruction:https://youtu.be/rUtDfadf8Jk
 * Watch introduction video to millis(): https://youtu.be/u2HsiTS8niQ
 
Get this code and other Arduino codes from Robojax.com
Learn Arduino step by step in structured course with all material, wiring diagram and library
all in once place. Purchase My course on Udemy.com http://robojax.com/L/?id=62

If you found this tutorial helpful, please support me so I can continue creating 
content like this. You can support me on Patreon http://robojax.com/L/?id=63

or make donation using PayPal http://robojax.com/L/?id=64

 *  * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.* 
 * This code has been download from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
const int LEDpin = 3;
const long onDuration = 100;// OFF time for LED
const long offDuration = 500;// ON time for LED
int LEDState =HIGH;// initial state of LED

long rememberTime=0;// this is used by the code

void setup() {
  pinMode(LEDpin,OUTPUT);// define LEDpin as output
  digitalWrite(LEDpin,LEDState);// set initial state
}

void loop() {
  // Robojax LED blink with millis()

 if( LEDState ==HIGH )
 {
    if( (millis()- rememberTime) >= onDuration){   
    LEDState = LOW;// change the state of LED
    rememberTime=millis();// remember Current millis() time
    }
 }
 else
 {   
    if( (millis()- rememberTime) >= offDuration){     
    LEDState =HIGH;// change the state of LED
    rememberTime=millis();// remember Current millis() time
    }
 }

 // Robojax LED blink with millis()
 digitalWrite(LEDpin,LEDState);// turn the LED ON or OFF

}// loop ends 

 /*
 * LED Blink with millis() with different time interval of ON and OFF time
 * Written by Ahmad Shamshiri for Robojax.com and Robojax YouTube channel
 * written on Aug 05, 2019 in Ajax, Ontario, Canada at 12:41
 * Watch video instruction:https://youtu.be/rUtDfadf8Jk
 * Watch introduction video to millis(): https://youtu.be/u2HsiTS8niQ
 
Get this code and other Arduino codes from Robojax.com
Learn Arduino step by step in structured course with all material, wiring diagram and library
all in once place. Purchase My course on Udemy.com http://robojax.com/L/?id=62

If you found this tutorial helpful, please support me so I can continue creating 
content like this. You can support me on Patreon http://robojax.com/L/?id=63

or make donation using PayPal http://robojax.com/L/?id=64

 *  * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.* 
 * This code has been download from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
const int LEDpin = 3;
const long onDuration = 100;// OFF time for LED
const long offDuration = 500;// ON time for LED
int LEDState =HIGH;// initial state of LED

long rememberTime=0;// this is used by the code

void setup() {
  pinMode(LEDpin,OUTPUT);// define LEDpin as output
  digitalWrite(LEDpin,LEDState);// set initial state
}

void loop() {
  // Robojax LED blink with millis()

 if( LEDState ==HIGH )
 {
    if( (millis()- rememberTime) >= onDuration){   
    LEDState = LOW;// change the state of LED
    rememberTime=millis();// remember Current millis() time
    }
 }
 else
 {   
    if( (millis()- rememberTime) >= offDuration){     
    LEDState =HIGH;// change the state of LED
    rememberTime=millis();// remember Current millis() time
    }
 }

 // Robojax LED blink with millis()
 digitalWrite(LEDpin,LEDState);// turn the LED ON or OFF

}// loop ends  

Arduino Milis() and Micros() without Delay

https://rudysarduinoprojects.wordpress.com/2019/02/10/fun-with-arduino-13-timer-with-millis-no-delay-multitasking/

#define INTERVAL_1 200  // [ms]
#define INTERVAL_2 1100  // [ms]
byte led_1;
byte led_2;
unsigned long time_for_action_1;
unsigned long time_for_action_2;

void setup() {
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
}

void loop() {
  if (millis() > time_for_action_1) {
    time_for_action_1 = millis() + (unsigned long)INTERVAL_1;
    led_1 = !led_1;
    digitalWrite(8, led_1);
  }
  if (millis() > time_for_action_2) {
    time_for_action_2 = millis() + (unsigned long)INTERVAL_2;
    led_2 = !led_2;
    digitalWrite(9, led_2);
  }
}

Matrix Max7219 with 2 or 3 or More Design Pictures

https://youtu.be/2rZWN1IcZpA?si=lzkYUDrVhY3a4ZX2

How to use SPI (Serial Peripheral Interface) in Arduino to Communication between two Arduino Boards

https://circuitdigest.com/microcontroller-projects/arduino-spi-communication-tutorial

Connect Two Arduino Boards Using I2C Communication Protocol

https://electropeak.com/learn/connect-two-arduino-boards-using-i2c-communication-protocol/#google_vignette

USB Keyboard LCD

https://www.hackster.io/michalin70/connect-a-usb-keyboard-with-an-arduino-50c077