This is tutorial number 1 from our series of Arduino tutorials and in this part I will talk about blinking an LED using the one already available on the Arduino Uno board or using an external LED to ...

By building this project, you’ll master: Digital input handling – How Arduino reads button states Output control – Turning LEDs on/off programmatically Circuit design fundamentals – Why resistors are ...

You could put the Arduino in deep sleep, if you wanted to and that LED will still blink. With a little work, you could probably adapt this idea to any number of circuits out of the 555 playbook ...

He then used his Arduino to interface with the ATtiny85 and provide the code powering the effect. Full details can be found at the source link below. Super Spooky Evil LED Eyes of Doom | Instructables ...