Have you ever been driving down the highway when a storm came up suddenly, darkening the skies to the point that you needed your headlights to drive safely, even though there was no rain? If you ever noticed, around the point that the skies started to darken, the streetlights would probably come on at a certain point or start to flicker.
There’s no one in a secret room controlling all of the streetlights - so how do they come on? It’s not a timer, because there’s no way to accurately predict when storms will come up, and even so, the length of day varies through the year, making timers effectively useless. The secret lies in a simple, yet remarkably effective, device known as a photocell sensor.
How a Photocell Sensor Works
A photocell sensor is a special device that is sensitive to changes in light. They have a wide variety of applications, but when used to control lighting infrastructure, their basic purpose is to enable a light fixture to be switched on or off, passively and remotely, in response to changes in ambient lighting. Often this keeps lights lit from dusk to dawn, but it can also enable them to be responsive to changes in the weather.
The sensor itself consists of a semiconductor material that is built into a portion of the circuit and controls the flow of electrons around the circuit, and thus to the light bulb. When light strikes the semiconductor material, it opens a switch and the electrical input to the light is shut off.
This is a very high-level view, but in other words, when it’s light out, these light sensors shut off the lights. When it’s dark, the sensor allows the switch to be closed and the lights come on.
How They Improve Safety
One of the reasons that a photocell sensor can be a worthwhile investment (although some lights come with sensors already built-in) is because they can potentially improve safety. Outdoor areas like parking lots and roadways are much less safe without ambient lighting, which fluctuates throughout the day.
Timers are ineffective, because the sunrise and sunset times vary throughout the year, and worse yet, conditions like storms are even more unpredictable and could necessitate additional lighting at the drop of a hat.
Photocell sensors enable lighting infrastructure to automatically respond to these changing conditions as they arise, are more accurate and responsive than timers, and provide a passive solution.
How They May Be Cost-Savers
What an organization could do is set a timer to have the lights come on before it actually gets dark and stay on until it is light again (although this doesn’t solve other problems associated with storms and other atmospheric conditions that are highly unpredictable).
The problem here is that timers, though they are in some ways highly effective at cutting back on wasteful energy expenditures, are highly ineffective at controlling outdoor lighting sources. A photocell sensor enables lighting to come on only when necessary and to switch off when the ambient light levels return.
This is responsive and only expends electricity when the situation calls for it, making this approach one of the most energy-efficient methods out there for remote control of lighting infrastructure.
The Difference between a Photocell Sensor and a Motion Detector
There is one other solution for homeowners that might be more practical than a photocell sensor, simply because not all lighting needs to run all of the time, even when it is dark. Some lighting, such as security lighting or small-scale area lighting, is only necessary when there are people in the area.
For situations similar to these, a motion detector might be more practical than a photocell sensor. Whereas a light sensor would keep the lights on throughout the night (or whenever it was dark) a motion detector would switch the lights on in response to movement, shutting them off again after a predetermined period of time.
If you’re concerned about energy expenditure, then a motion sensor might be a more reasonable option for your area lighting. It’ll only come on as needed, and will remain off the rest of the time, saving money in the process.
Contact Atlanta Light Bulbs for More Information
If you still have questions about how photocell sensors or motion detectors work, or you want to know what your options are, please feel free to get in touch with us. We’ve been serving residences, commercial settings, and industrial locations for 40 years and we’d be glad to help you - no job is too big or too small, and we pride ourselves on our service.
Whether you just need a single photocell to control the light over your shed or you’re looking to outfit an entire stadium with sensors to keep the lights on in the dark, we’re here to help. Please visit our collection of photocell sensors and contact us if you need further assistance regarding specifications or pricing. You can reach us at 1-888-988-2852 or at [email protected].