Arduino project · Motors and movement · Medium
Solar Tracker (Single Axis)
Two light sensors on the left and right of a panel make a servo turn the panel towards the brighter side.
What you will learn
- How a solar tracker follows the sun
- How to compare two sensors
- Why a small margin stops the panel from shaking
How it works
The servo starts at the middle (90). If the left sensor (LDR1) is brighter than the right sensor (LDR2) by at least 8, the panel turns to 135. If the right one is brighter, it turns to 45. If both are about equal, the panel stays in the middle. The Compare step checks one sensor against another, so you do not need to set a fixed number.
Try this next
- Move in small steps instead of two fixed angles.
- Add a dark shade between the sensors to improve the difference.
- Add an LCD that shows both light levels.
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 solar panel following the sun
Change the two light sliders. The sun moves to one side and the servo tilts the panel towards it, to catch more sunlight.
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 = where the sun is
- Servo = the panel tilt