Skip to content
JEJunior Engineer LabPico W + micro:bit course
11micro:bit · MakeCode 35 minutes

LDR nightlight

External light sensor with calibrated thresholds and hysteresis.

LDR nightlight project
Illustration of the finished idea. Build from the diagram and connection table, not the photo.

Lesson goal: Read an LDR divider on P1 (0..1023) and switch the P0 LED with LOW/HIGH thresholds that keep state in between.

Open MakeCode

Section 1

Understand

  • LDR
  • voltage divider
  • calibration
  • hysteresis
  • 13V → light sensor → P1 junction → 10 kΩ → GND.
  • 2Below LOW: lamp on. Above HIGH: lamp off. Between: no change.
  • 3Calibrate LOW and HIGH from your own dark and bright readings.

Safety first

  • Unplug the USB cable before you add, move or remove any wire. Plug back in only after an adult or you have re-checked every connection against the table.
  • micro:bit pins are 3 V logic. Never connect 5 V, a battery pack or anything from a 5 V supply to any ring, port or the 3V ring.