How Does a Garage Door Sensor Work? Why Are They So Important?
Have you ever asked yourself, how does a garage door sensor work? In this article I will explain how these important sensors work and throw in some tips to keep your garage door working smoothly and safely.
Why do garage doors need sensors?
In the early 90’s it became a regulated law that all new garage door openers must use sensors to prevent people from getting hurt or even killed by a moving garage door.
As a home owner your garage door opener has these sensors, there theory is simple yet many people still wonder how they work.
That’s why this article aims to answer the question, how does a garage door sensor work? in simple terms.
There are 2 Garage door sensors we will cover in this article ….
- Closing safety sensors
- Remote opening sensor
How Do Garage Door Sensors Work?
First lets take a look at the safety sensors, these are designed to stop the garage door’s movement if something comes under the door while it’s going down.
How the safety sensors work.
The garage door for your home is VERY heavy. High tension delivered by heavy duty springs are the only thing that assists the garage door opener. Many people don’t know this, without the springs assisting in lifting that beast of a door the door is not moving anywhere.
I’m sure I don’t need to tell you, there have been many accidents involving garage doors. People have been killed or seriously hurt because of a garage door continuing to close while they were in the wrong place at the wrong time, not to mention property damage as well.
The safety closing sensors on a garage door are located about 6 to 8 inches above the floor on each side of the door opening.
There is a “primary” sensor that shoots a infrared beam across the door opening to the second sensor. This beam is constant between the two sensors, if that beam is blocked for any reason the garage door will immediately stop and go back up. Think of these safety sensors as a invisible string that breaks if you trip over it.
What if my garage door won’t close?
Chances are these safety sensors are blocked or misaligned if you hit the down button and the door moves a little and runs back up even though nothing is under the door. Be sure to check the sensor alignment, there is usually a small led on each sensor that stays lit when they see each other properly. The brackets holding these sensors can get knocked out of alignment over time.
How the remote opening sensor works.
Pulling into the garage without needing to get out of the car is a convenience we take for granted. That little remote in your car is awesome, how does it work?
Garage door openers use a “rolling code” that changes every time the remote is used. When the door opener is synced to the remote they are both in sync with each other meaning that the next time you hit the remote it sends the correct code to the opener and activates it. After the activation the code changes, because both devices are in sync with each other they work seamlessly together.
This marriage of remote and opener relies on a simple radio frequency or infrared signal.
Some quick garage door tips
Hopefully this article explained how garage door sensors work and why they are important. Lucky for us all new garage doors have these safety and convenience features as standard equipment.
Thanks for reading!
Scoot is a Dad, ASE certified mechanic, and blogger. He has been in the automotive business for over 25 Years.