Arduino project · Light sensing · Easy
Auto-Brightness Night Light
The darker the room, the brighter the lamp glows, and it fades out in daylight.
What you will learn
- How to invert a reading (dark gives bright)
- How a light sensor controls a dimmable lamp
- How phone screens set their own brightness
How it works
The Map step turns the light reading (0 dark, 100 bright) upside down into the LED brightness.
Try this next
- Set a minimum glow so it never goes fully dark.
- Add a button for manual override.
- Add a PIR so it lights only when someone is near.
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 night light that dims with the room
The darker it gets, the brighter the lamp glows. Move the light slider and watch the room.
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.
- Light sensor = daylight in the room
- Dimmable LED = the night light