Photocells and motion sensors are electronic devices you can use to manage indoor or outdoor lighting. These sensors improve the security and safety of your home, automatically turning on lights when it gets dark or they detect motion. They also save energy by turning themselves off when extra light is unnecessary. Explore the differences between photocells and motion sensors and find out how these products, along with dimmers and other controls, can enhance your home’s lighting system.
There are a variety of photocells available today.
Plug-in photocells work with a standard wall outlet and control a pass-through plug. They're a convenient way to turn a single table or floor lamp on and off.
Lamp or candelabra base photocells screw into a light bulb socket, turning almost any lamp or permanent fixture into an automatic lighting system. You’ll need to install one of these devices in each socket for proper operation.
Line-voltage, wired photocells control an entire electrical circuit and are an ideal way to manage security or landscape lighting.
Motion Sensors in Action
The main difference between photocells and motion sensors is that the former detects changing light levels, and the latter reacts to physical movement. There are two types of motion detectors. Active models emit light, radio or ultrasonic sound. Movement in the detection area changes the reflected signals and activates the sensor. Some of these devices can even sense motion around corners. Passive motion sensors detect the infrared energy given off by warm objects such as animals or people. When these warm spots move, it triggers the sensor and any connected electrical circuit.
Many motion sensors use a combination of detection methods to provide enhanced coverage and eliminate false positives. Devices designed for outdoor use often include a photocell function that turns the system off during the day, which conserves energy. The adjustable timers built into some sensors lets you control how long the attached lights remain active after it detects motion.