How Does A Garage Door Sensor Work

The invention of garage door sensors has ensured the safe operation of garage door opener systems for garage owners everywhere. While automated garage systems are convenient and affordable for many individuals, they can also be dangerous without the proper safeguards in place. Garage door sensors help individuals gain access to convenience without the threat of injury to themselves or those they love. How do garage door sensors work? How do you maintain them? Let’s find out!

Getting to the Basics

garage door sensor
garage door sensor

Your garage door sensors perform a vital function. They notify your garage door system of any potential obstruction that would disrupt the downward trajectory of the garage door. Garage door sensors are purposed to prevent injury to you, your pets, or your loved ones. They can also prevent damage to the garage door and the garage system itself. 

How do they do it? It’s all about having an extra pair of “photo eyes” to keep an eye out for anything that would interfere with the path of the door.

Photo eyes situated on each side of the garage door opening transfer an electricity-formed infrared beam between them. Each photo-eye needs to “see” the other before the door can descend and fully shut. If the infrared beam is “tripped” or its “communications” are blocked, the sensors send a (warning) signal to the system. This causes the door to retract in response–protecting darting children, pets, and busy adults from the descending door. It also keeps objects below from damage if they are lying in the door’s direct path.

Be on the lookout for red blinking LED lights on the wall control unit of the garage opener system. It’s an obvious signal that there is something wrong with the sensors and needs attention. You may be able to fix the problem on your own. Don’t panic! After you do some educated troubleshooting, you’ll be able to decide how to get your garage door system back on track.

Size of garage door

buying garage door
buying garage door
The primary thing that you will need to consider for buying a garage door is its size. The standard size for the single-car garages is around 8-9 feet wide, and its height may vary from 7-8 feet. For double car garages, the width may be double in size, and height might be the same unless the garage contains a truck. The height of the garage, including it, will be around 10 feet tall. Prior to selecting a garage door you will need to have the opening measured by a professional to insure that you get the right fit.

Simplifying Life with Sensors

The 1990s is known for peace and prosperity–and the rise of the World Wide Web. It is also the decade that saw the emergence of garage door sensor laws. 1993 is the year that our federal government mandated that every garage door opener seller install garage door sensors. Since then progress has been made to boost convenience in the garage industry. 

Technology has continued to evolve since garage door sensors became a requirement. An infrared radio signal starts the motorized pulley/track of your garage system by remote power. If your garage doors photoelectric sensors/photo eyes are unobstructed–the door will close.

Some garage systems can be operated–via your home. Wiring creates instant “open door” communication. Current garage door opener systems often use wiring and remote power. Now as we enter another decade, smart technology is taking garage systems to “next level.”

Garage door systems are now quickly becoming operational from anywhere in the world. Smart technology and safety will soon be entirely synonymous with garage systems. Garage door sensors are evolving as some models stay connected with Wi-Fi. They’ll let you know if your garage door is open or closed by communicating with your smartphone. It’s the ultimate safety system to ensure your door opens for the right people and shuts to keep uninvited guests out!

Types of garage doors

The most used materials for the garage doors are wood, steel, fiberglass in the basic configuration. Here are some options you will want to consider when purchasing a garage door.

Single-Layer: Contains a single outer layer of material that is light weight and easily affordable. A single-layered garage door contributes minimal insulation.

Double-Layer: A layer of polystyrene will be present between inner and outer skins of the garage door. This layer provides an insulating value from R-4 to R-7.

Triple-Layer: A layer of steel inside the door to protect the insulating layer. A triple-layered garage door is the strongest and provides high thermal resistance above R-15 that are available in the market.

FAQ’s on Garage Door Sensor

If your garage opener system isn’t working, it can serve you well to troubleshoot garage door sensors first. You can avoid the repair drain on your bank account by making positive assumptions early on. A simple misalignment of the photo eyes can cause your garage system to act in peculiar ways. Here are some common questions that could be attributed to garage door sensor problems:  

  • Why is my garage door only closing partway?
  • My garage door seems to have a mind of its own. Why is it reversing without me pushing a button?
  • The lights are flickering on my sensors photoelectric eyes, what do I need to do?
  • When opening the garage door, it’s a hit and miss. Sometimes it works–sometimes it doesn’t. What’s up?
  • I try to activate the door opening feature from my car and driveway–it’s not working. Do I need to call a garage system repair specialist?
  • My door is great at opening but rarely closes–what do I do?


For those who want to keep repair costs low and spirits high, do a thorough garage door sensor check. It will help you keep your sanity and your money in your wallet! Quick fixes can save you money. It is possible of course that it could require garage door repair professionals. Knowing the difference can help you avoid costly mistakes.

Solutions to Sensor Your Next Step

How do you problem solve garage door sensor issues? Identify the factors that can impact the efficacy of the sensors themselves. Check below to see if any of these factors could be negatively impacting your garage system. 

Common sensor problems include:

  • Dirt stained photo eyes
  • Sunlight affecting the sensors
  • Sensors that are misaligned
  • Loose or shorted wiring


What can you do about it? Now that you know how your sensors work–you can find out how to keep them working diligently for you. Some sensor problems you can tackle on your own. Other issues like shorted or loose wiring may require additional help from trained repair professionals. Here’s what you can do to keep your sensors functioning at a high level.

Keep them clean.

If you notice that your sensor is dirty, clean it! Warm water and a little soap can work wonders! Sometimes the grime can disrupt communication between the sending and receiving sensors. 

Once you’ve done that, scan the area for bulky items that may be blocking the infrared beam. The outside area near the sensors can hinder your garage sensors from doing their job. Clear away any low hanging branches, weeds, or debris to ensure nothing interferes with the trajectory of the sensor beam.

Readjust the sensors as needed.

Have you noticed that your garage sensors have become nocturnal? If your photoelectric sensors communicate better in the dark, they may be suffering from direct sunlight exposure during daylight hours. 
Your sensors have mirrors inside them. If the mirrors meet direct sunlight, sensors are affected. Usually, a misalignment has occurred. A slight repositioning may alleviate the problem.

If your door isn’t shutting entirely or reversing instead of descending, your sensors may need a more in-depth adjustment. Vibrations from the garage door opening and closing over time can cause your wall-mounted sensors to fall out of place.

Sometimes tightening wing nuts can solve the issue. Other times if the sensors have been bumped more vigorously or weren’t attached appropriately–it’s time to grab a measuring tape! Are the sensors at the appropriate height? Does each receptacle “see” the other photoelectric eye?

If they are badly misaligned, you may have to get a little more hands-on! Once the sensors are level with each other and affixed tightly to your garage’s inner wall, your garage door should function properly. If not–it could be a sign to recruit the professionals.

Tighten it up.

For one last troubleshoot tip, check your sensors’ wiring. Faulty wiring can cause a host of problems for your garage door system. First, shut off the power. Never touch wires without getting rid of the power source. If your sensors have any loose wires or fittings, you may be able to push them into place. There still could be a problem with the wiring. Instead of a loose wire, there may be a wire that has shorted. Unless your a trained electrician, now would be the time to call in a professional. Fresh eyes can also help you determine what your next step should be.

Tools and Tips

If your garage door sensor is misaligned, you’ll save time and money understanding what you need to fix the problem. You’ll need: 

  • Phillips head or slotted screwdriver
  • Wipe cloths
  • Soap and water
  • Low sunlight

Garage sensor professionals recommend doing some prep before fixing misaligned garage door sensors. It’s best to fix the sensors on a day with low sunlight. Direct sunlight can affect the sensor’s infrared beam. Sometimes correcting the positioning is all about trial and error. Outside interfering factors can slow the process.

Clear the area of objects that can affect the infrared beam’s trajectory. Always clean the photo eyes before and after you adjust the sensors. Control the environment and control the amount of time and sweat equity it takes to adjust the sensors.

Use the buddy system. The wall control unit needs to be in your sightline. An extra pair of eyes can help in a big way! The red flashing LED light on the wall control is your warning signal–letting you know the sensor is out of alignment. As you move the sensor unit, have your friend watch for the light. Once you’ve centered the sensor unit so that the beam is aligned, the red light should stop blinking. It’s letting you know that the sensor is now positioned correctly. Then after the red light has stopped you’ll need to use your screwdriver to secure the unit in place.

It Works for You

Garage door sensors are put in place to create safe environments for you and your family. If you want to ensure they continue to keep you safe, learning how they work is a great first step. Infrared beams, electrical currents, photoelectric eyes, and invisible tripwires are “fancy” speak for a helpful technology that makes the day-to-day more convenient for you. It all leads to one thing–balance. Just like you, sensors work well when everything is aligned for success! If you need more details on how sensors work–make sure to contact your garage system professionals!