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LDR Light Sensor

An LDR (Light Dependent Resistor), also called a photoresistor, changes its resistance based on the amount of light falling on it. This allows your micro:bit projects to measure brightness and respond to changes in ambient light.

What It Does

The LDR outputs a varying voltage depending on light intensity. Your program can read this as an analog value (ranging from dark = low value to bright = high value) and use it to trigger actions such as turning on lights or adjusting displays.

Real-World Applications

Light sensors are used in countless real-world systems, such as:

  • 💡 Automatic Street Lights – Turning on at night and off in the morning.
  • 📱 Smartphones – Adjusting screen brightness based on ambient light.
  • 🏠 Smart Homes – Controlling curtains, lamps, or garden lighting automatically.
  • 🤖 Robotics – Light-following robots or obstacle detection.
  • 🔒 Security Systems – Detecting changes in light for alarms or monitoring.

Using an LDR, students learn how to make their prototypes react intelligently to environmental light conditions.

✅ With the LDR, you can build projects that respond to light—from night lamps and alarms to smart energy-saving devices.

Connection to the breakout

  • Connect the LDR to the port 3v3, GND and P2 (Blue) LDR connection port

  • Connect the OLED to the port P20, P19 , GND and 3v3 (Yellow) OLED connection port

  • Connection of LDR and OLED with the breakout board

LDR and OLED connection

Code