Lenny Murte

Dual-Axis Solar Tracker

Optimizing energy collection with a smart solar panel (prototype).

Role
Embedded engineer
When
Where
Prépa (TIPE) · Paris
Status
Embedded Cleared

ContextBriefing

This was my TIPE, the research project every student carries over the two years of prépa (the French preparatory classes for engineering schools). The starting idea was simple: a fixed solar panel misses a good part of the energy it could collect, because the sun keeps moving all day long, and I wanted to see how much you actually gain by making the panel follow it.

I built a prototype on an Arduino: a small panel mounted on two servo motors, one per axis, with light sensors around it that compare how much light each side receives. I first drew the wiring in Fritzing, then assembled it and tested it outside, in full sun.

The solar tracker prototype on a rooftop: a small solar panel with light sensors on each side, mounted above an Arduino board and its wiring, on a red shoebox.
The prototype, tested on a rooftop in full sun.
A laptop showing the tracker’s wiring diagram in Fritzing: the Arduino board, two servo motors, sensors and a display connected by colored wires.
The wiring, first designed in Fritzing.

What I didObjectives cleared

  • A PID control loop in C/C++ running in real time on a microcontroller with very little memory and compute.
  • The light differences between the photoresistors (LDRs) turned into commands for both motors, under tight timing constraints.
  • Noisy readings filtered and gains tuned by hand, without going over the board’s compute budget.

Hardest problemBoss fight

Noise against responsiveness

Light sensors are noisy, and a loop that reacts to every flicker ends up oscillating around its target without ever settling. I had to filter the readings and tune the PID gains little by little, until I found the right balance between a tracker that stays stable and one that reacts quickly when a cloud goes by.

ResultsRewards

  • +25% energy capture efficiency

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