Today we will make a 2 LED flasher using Arduino (UNO)
Usual we use a transistors circuit to make two LED flasher. This we will study programing C code on Arduino. It is easy to learn. Step to step by Chayapol. Lets go!

Figure 1 Define pictograms,easy to understand

Figure 2 Set the diagram programing

Figure 3 Put code in programing
Read also: DIY Flashing Bicycle LED Taillight Circuit
Then, we open the Arduino IDE software. Next,write the code below
CODE
void setup() { pinMode(13, OUTPUT); pinMode(12, OUTPUT); } void loop() { digitalWrite(13, HIGH); digitalWrite(12, LOW); delay(1000); digitalWrite(13, LOW); digitalWrite(12, HIGH); delay(1000); }

Figure 4 programing on Arduino IDE
And then, when you’re done. Press Ctrl+R to Compile. For check it.
Parts you will need:
Arduino
2X LEDs
2X 470 ohm resistor
jumper wires

Connect the parts as Figure 5
Then, apply USB port to computers
Finally, Click to Sketch>Upload code to the arduino board.
We will see 2 LEDs alternately blink as Figure 6.

And video below
-First we set time delay is 1 S
-Second we set time delay is 0.1 S (LED flasher faster)
-Third we set time delay is 3 S (LED flasher slowly)
Related circuit: 1.5V LED flasher circuit using transistor, output one LED to 5 LEDs with only one AAA battery.
we can use Arduino to make a 2 LED flasher but we have to adapt the We can use Arduino to make two flsher lights, LED work light, which is controlled by the internal code Arduino. Good luck