Be a Control Freak: Understanding Wall, Ceiling and Photocell Sensor Solutions

a guest post by Tim Hogan, Vice President – Education Market at Acuity Brands Lighting

Understanding Wall, Ceiling and Photocell Sensor Solutions

To get started with a sensor project, we ask folks to provide a floor plan to Graybar and our Controls Specialist who goes through the whole layout of your building and marks up appropriate sensor technology for the space based on the room size, dimension and whether or not you need more than one sensor.

Wall Mounted Solutions

There are two kinds of sensors mounting solutions, wall mounted and ceiling mounted. The wall mounted is the simplest, but the ceiling mounted gives you a little more flexibility.

Wall sensors are very simple to install. You simply take the old switch out of the wall, wire up the hot ground and put it back in. It has sensitivity controls baked into it. It’s very controllable. This is where you want to make sure you’ve done the proper testing because reconfiguration involves engaging facility management to recalibrate.

Wall mounted can be added to any space that is up to about 20 x 20 or a typical small office. You typically wouldn’t put them in a bathroom or any kind of small space or closets. They can come in multiple configurations but you have single technology sensors and dual technology sensors for wall sensors.

It’s important to choose the right kind of wall switch for the right kind of space. A copy room with people moving in and out would require a different sensor compared to an office setting where people are sitting which might need a microphonic sensor and a passive infrared.

Ceiling Mounted Solutions

Ceiling sensors are typically Passive Infrared and have a much broader spectrum of coverage in odd shape rooms and come in single and double technologies.

Photocell Sensors

The other sensor that is very important to consider is the photocell. Photocells can be very effective in switching lights off, which is a good thing. They are more effective if you have LED sources in the space and it allows you to dim the LED light fixture to compensate for the contribution of daylight. So if I have a certain amount of lighting contributed by daylight, the photocell tells the fixture to dim the appropriate amount so that the occupant has an appropriate amount of lighting.

A couple things that are useful about this, photocells recognize light changing and have algorithms programmed in them so that when a cloud passes over, they don’t instantly turn the lights up to full bright.

This algorithm recognizes that the lights have been dim for only a few seconds. “I will give you a few seconds and then I will start easing up the ramp speed”.

It does that change of light intensity up and down in a thoughtful way. If sensors could think! There is programming so that it’s not distracting to the user.

I was in an older department store not too long ago and there were a lot of skylights, lights and photocells. The lights were turning on and off – it was like a really bad concert. It was very distracting. So one of the things you really want to do is make sure you have a photocell that is able to adapt and provide a very comfortable experience.

X Point Sensors

A very exciting new technology Acuity has is called X Point. These sensors are wireless and powerless. The wall switch itself requires no lines to it. It requires no power to it. The act of flipping the switch creates enough energy to generate the wireless signal to the other equipment in the room to take action.

X Point is now available and is shipping and is optimized for a space where wireless is ideal. We have five different communication protocols for our sensor offers.

The occupancy sensors and the photocells are also wireless and require no power. They get their power from the ambient light during the day.

Proximity Sensors

For some reason when you go outside, we start calling sensors proximity sensors. It’s not very attractive, but these sensors can be bolted on. It works, but newer fixture designs have the sensors embedded.

The Pole Mounted Sensor is mounted at a lower level like a parking garage. Parking garages have sensors independent from the fixtures and they recognize that there is activity on the floor. The sensor will turn the light on for a whole zone or floor.

We don’t want to just light up the person walking through the space. The boss says that’s the equivalent of lighting up the victim and not the perpetrator. So that sensor needs to understand that I’m lighting up the whole space so that the occupant can feel comfortable and see and know that they are safe for the entire floor.

It’s all about choosing the right technology for your space.

Ready to start a sensor project? Have a Graybar Lighting Specialist contact you.

Stay tuned for the next article: Check your Stairwells for Fast ROI.

Tim Hogan

Tim Hogan works with educators, facilities directors and design professionals to improve lighting solutions for both K-12 and Higher Education campuses. His articles have been published in numerous magazines for education facility designers and managers. He is a frequent presenter at local, regional and national events. Acuity Brands is one of the world's leading providers of lighting equipment, solutions and services.


The opinions expressed by authors herein and those providing comments are theirs alone, and do not reflect the opinions of Graybar Electric Company, Inc. or any employee thereof. Graybar Electric Company, Inc. is not responsible for the accuracy of any of the information supplied by the authors or commenters. All the information on this website is published in good faith and for general information purpose only. Graybar Electric Company, Inc. does not make any warranties about the completeness, reliability and accuracy of this information. Any action you take upon the information you find on this website, is strictly at your own risk. Graybar Electric Company, Inc. will not be liable for any losses and/or damages in connection with the use of our website.