Light-Sensitive Outdoor Light

Introduction

When the sun goes down, many homeowners use outdoor lighting as a security measure to illuminate driveways, sidewalks, and patios. Others use low voltage lighting systems to highlight landscape features, such as trees, gardens, and artwork. A traditional time-based system needs constant adjustment as the actual time for the setting sun is driven by the seasons of the year. A sensor-driven dusk-to-dawn system is much more energy-efficient. As a STEM extension to the “Light, Brightness, and Distance” experiment, you can use a Vernier Digital Control Unit (DCU), Light Sensor, and a white LED or lamp to build a sensor-based outdoor light.

Objectives

• Turn on a light when the ambient light level is low.
• Control a sensor-based system with the DCU.

Reference Experiment

• “Light, Brightness and Distance” – Experiment 29 from Physics with Vernier
• “How Bright is the Light” – Experiment 25 from Physical Science with Vernier
• “Reflectivity of Light” – Experiment 7 from Middle School Science with Vernier