ElecFreaks
Octopus Analog Photocell Brick OBPhotocell
The Octopus Analog Photocell Brick is a light-dependent resistor (LDR) module from the ElecFreaks Octopus Electronic Bricks series. It uses a cadmium-sulfide...
The Octopus Analog Photocell Brick is a light-dependent resistor (LDR) module from the ElecFreaks Octopus Electronic Bricks series. It uses a cadmium-sulfide (CdS) photocell that changes resistance based on ambient light levels — the brighter the light, the lower the resistance. With its 3-pin connector, it plugs directly into sensor shields and expansion boards with no soldering required.
Photocells are ideal for detecting basic light level changes such as "light vs dark", "something blocking a sensor", or "which direction has more light". They're inexpensive and easy to use, though not precise enough for exact lux measurements.
Key Features
- CdS Photocell (LDR) – Resistance varies with light intensity
- Analogue Output – Read light levels via an analogue input pin
- 3-Pin Connector – Buckled wire interface for secure, breadboard-free connections
- Plug and Play – No soldering; connects directly to sensor shields and OCTOPUS:BIT
- Wide Compatibility – Works with Arduino, micro:bit (via OCTOPUS:BIT), and other MCU boards
Ideal For
- Light vs dark detection for automated projects
- Break-beam and object detection sensors
- Ambient light level monitoring
- Beginner Arduino and micro:bit projects
- STEM education and classroom activities
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- break-beam
- A sensing method where an emitter sends a beam of light to a receiver, and an object is detected when it blocks the beam. It is useful for tripwires, counters, and object detection where you need a clear interrupted/not-interrupted signal.
- LDR
- A light-dependent resistor is a component whose resistance changes with light level. It is useful for simple brightness sensing, and an ADC board is needed to turn its changing analogue voltage into numbers a microcontroller or computer can read.
- lux
- Lux is the standard unit for measuring how much light falls on a surface, similar to how a light meter reports brightness. A sensor that outputs lux gives readings that are easier to compare between rooms, outdoor conditions, and different projects.
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Sensors & Input
Related Tutorials
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