☀ Solar Power

Harvest sunlight to power microcontrollers — sustainable, off-grid computing

Overview

Learn how solar energy works from panel to microcontroller. Build solar-powered systems that charge batteries, regulate voltage, and run ESP32 projects independently of mains power. Monitor energy yield on the shared dashboard.

🧰 Kit List

  • 6V solar panel (1W–2W, small form factor)
  • TP4056 lithium charge controller module
  • 18650 lithium-ion battery + holder
  • MT3608 boost converter (3.7V → 5V)
  • AMS1117 3.3V voltage regulator (or use ESP32 onboard)
  • ESP32 development board
  • INA219 current/voltage sensor module (I2C)
  • Multimeter (for voltage/current measurement)
  • Breadboard and jumper wires
  • Diode (1N5817 Schottky) for reverse polarity protection
  • Optional: second solar panel for comparison testing

🎓 What You Will Learn

  • How photovoltaic cells convert light to electricity
  • Solar panel characteristics: voltage, current, power curves
  • Lithium battery safety and charge management
  • Voltage regulation: why 6V solar → 4.2V battery → 3.3V MCU
  • Measuring current and voltage with INA219
  • Energy yield calculation (Wh) and efficiency
  • Sustainability and renewable energy concepts
  • Power budgeting for embedded systems

🌐 Cross-Curricular Links

  • Science: Photovoltaic effect, energy conversion, efficiency, circuits
  • Maths: V=IR, P=IV, energy (Wh), percentage efficiency, graphing yield
  • Geography: Renewables, climate, latitude & solar angle, sustainability
  • DT: Panel mounting, weatherproof enclosure, 3D printing
  • English: Sustainability argument writing, data-driven reports
  • PSHE: Climate change, personal responsibility, green technology

🛠 Key Skills

  • Multimeter use: measuring voltage, current, continuity
  • Power supply circuit design
  • MicroPython: I2C sensor reading (INA219)
  • Data logging and energy calculations
  • Safety awareness with lithium batteries

Projects

From measuring sunlight to running a fully solar-powered weather station.

Project 1: Meet Your Solar Panel

KS3

Use a multimeter to measure the solar panel's open-circuit voltage and short-circuit current in different light conditions. Understand what the panel can deliver.

Project 2: Charge a Battery

KS3 / KS4

Connect the solar panel to a TP4056 charge module and 18650 battery. Monitor the charging process. Learn about lithium battery safety and charge states.

Project 3: Power an ESP32

KS4

Add a boost converter to step battery voltage up to 5V. Power the ESP32 from the solar/battery system. Measure how long it runs on a full charge.

Project 4: Energy Monitor

KS4

Wire an INA219 sensor to measure solar panel voltage and current in real time. Calculate power (P=IV) and energy yield (Wh). Send data to the Node-RED dashboard.

Project 5: Solar Weather Station

Stretch

Combine solar power with the ESP32 Sensing strand. Build a fully off-grid weather station that monitors temperature, humidity, pressure, and its own energy generation. Dashboard shows environmental data and power status.

Project 6: Solar Tracker

Stretch

Link with the Actuators strand: mount the solar panel on a servo. Use LDRs to track the sun's position and maximise energy collection. Compare yield vs a fixed panel.

Baton Pass Checklist

Before you hand over to the next group:

  • Completed your digital project card with circuit photos
  • Solar panel charges battery successfully
  • ESP32 runs from solar/battery power
  • Power chain diagram (panel → charger → battery → regulator → MCU)
  • Energy yield data logged and graphed
  • Battery safety notes documented
  • 5-minute walkthrough for the next group