Circuit Library

Arduino Traffic Lights

This is a simple traffic light project that simulates the behaviour of European traffic lights: First Red. Then Red + Yellow. Then Green. Then Yellow. This repeats over and over. You can tweak the times for each stage in the code.

IR Remote Switch v2

This project shows you how to create a simple remote-controlled on-off switch that will work with most IR remote controls. And you only need four components to build it—an IR receiver, a capacitor, a JK flip-flop, and a relay module. You can connect whatever you want to control to the relay, and then use any IR remote control to turn it on or off.

555 Timer: Running LEDs (Knight Rider)

This circuit creates a light that "runs" back and forth using a 555 timer and a decade counter. It's effect is similar to the light bar on the car from the old television show Knight Rider. It's a really fun circuit to build. I once built a larger version of this for the inside of a party bus when I was a teenager. Unfortunately, I broke it the first day because I increased the voltage too much! But that's another story...

Scoreboard Display

A simple project that counts the number of times you've pressed the button. Can be used as a scoreboard display for a game. Or to keep tracks of things like how many cups of coffee you've had today.

555 Machine Gun

This "machine gun" circuit generates a sound that mimics the sound of a toy machine gun. It is based around a 555 timer IC in a feedback loop. Check out [this demo video](https://youtu.be/wSN8_ChDztw) to hear the circuit in action.

555 Timer: Blink LED

Here's how to build a simple LED blinker using a 555 timer. The 555 timer is configured as an astable multivibrator, which means the output will turn on and off repeatedly. With the chosen values, it will turn on and off about five times per second. Since the LED is connected to the output, it blinks =)