Arduino project · Light sensing · Easy
Automatic Street Light
Three street lamps switch on together at dusk and off at dawn.
What you will learn
- How one sensor can control many outputs
- How day and night readings differ
- Why street lights use a sensor instead of a timer
How it works
One LDR watches the sky. When the reading falls below 35 % all three white LEDs turn on. In the daytime they stay off, saving energy.
Try this next
- Make the lamps come on one after another using wait steps.
- Add a PIR sensor so lamps are bright only when someone is near.
- Add a fourth lamp.
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 street at dusk
Drag the light slider down in the simulator. When it gets dark, the street lamps in the real scene come on, just like the lamps outside your home.
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 above the street
- LED 1 to 3 = the three street lamps