Little Bird Circuits breadboard diagrams you can open in Fritzing Playground
PRP 3 — Light sensing with an LDR 4 parts · 7 wires · 2 views Download .fz Embed view

An LDR and a fixed resistor form a voltage divider. The junction goes to A0, so the board reads a voltage that changes with the light falling on the LDR.

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Shared from Little Bird Electronics. Opens in Fritzing — this image was created with Fritzing, and its part graphics are CC BY-SA 3.0.