Arduino project · Light sensing · Easy
Light Direction Indicator
Three LEDs show whether the light comes from the left, the right, or straight ahead.
What you will learn
- How to compare two light sensors
- How to show a direction
- How a sun sensor is made
How it works
Green means the left is brighter, red means the right is brighter and yellow means both are about equal. The Compare step checks one sensor against another, so you do not need to set a fixed number.
Try this next
- Add a buzzer when the light is exactly in the middle.
- Show the direction on a servo needle.
- Use ultrasonic sensors instead of light sensors.
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 light direction signal
The lamps tell you whether the light is to the left, right or in the middle.
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.
- Two light sensors = left and right
- LEDs = direction