Arduino project · LEDs and lights · Easy
LED Fade In and Out (Breathing Light)
An LED slowly glows brighter, then dimmer, like a sleeping computer light.
What you will learn
- What PWM is and why the pin needs a ~ mark
- How analogWrite sets brightness from 0 to 255
- How small steps make a smooth fade
How it works
Each step sets the brightness a little higher, then lower. The Arduino switches the pin on and off hundreds of times a second; the longer it stays on, the brighter the LED looks.
Try this next
- Make the steps smaller for a smoother fade.
- Make the fade slower with longer waits.
- Add a second LED that fades the opposite way.
The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.
Parts: sensors and actuators (tap to show or hide)
Try the inputs (virtual sensors)
Pins (you can change them)
| Part | Arduino pin (change it here) | How to wire it |
|---|
Every wire, one by one
Red rail = 5 V from the Arduino 5V pin. Black rail = GND. The coloured wires carry signals. Match the wire colours on the drawing to this list.
| # | Colour | From (part and leg) | To |
|---|
Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.
Quantities come from the parts you added. The store links open a search for that item on Robu.in, Amazon.in and ThinkRobotics, so you always see what is in stock today. Check the model, voltage and price before you order.
| # | Item | Qty | Search term | Buy / compare |
|---|
The PDF has the circuit sketch, pin table, every wire, sequence, full code, the parts list with store links, do’s and don’ts for each part, and the safety notes. The project file lets you come back and keep editing.
In the real world
A lamp that fades
The brightness of the lamp follows the PWM value your program sets.
Tip: use the gold tab at the bottom of the circuit drawing to pull the real-world view up over the Arduino board. Your parts stay visible above it, so you can press a button and watch the real scene react.
- Dimmable LED = the lamp