Garage door sensors work by creating an invisible infrared beam between two units that acts like a tripwire.
Here's a breakdown of how these essential safety devices function:
The Basics: Invisible Infrared Beam
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Two Units: The system consists of two sensors:
- A sending unit (also called a transmitter) that emits an infrared light beam.
- A receiving unit (also called a receiver) that detects the infrared light beam.
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The Beam: The sending unit constantly transmits an invisible infrared light beam to the receiving unit.
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Tripwire Effect: When the beam is unbroken, the receiving unit signals the garage door opener that the path is clear and it's safe to close the door. If something interrupts the beam (a child, a pet, an object), the receiving unit immediately stops the signal, preventing the door from closing or causing it to reverse direction if it's already closing.
Why Infrared?
Infrared light is used because it's:
- Invisible: Humans can't see it, so it doesn't create a visual distraction.
- Reliable: It's relatively unaffected by ambient light conditions.
- Safe: Infrared light at the power levels used in garage door sensors is harmless.
Placement and Safety
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Low to the Ground: Sensors are installed close to the ground (typically 4-6 inches above the floor). This ensures that even small obstructions are detected.
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Safety Feature: The primary purpose of garage door sensors is to prevent the door from closing on people, pets, or objects, greatly reducing the risk of injury or damage. Modern garage door openers are required to have these safety sensors.
Troubleshooting Common Issues
- Misalignment: If the sensors are misaligned, the receiving unit won't detect the infrared beam. You may need to adjust their position.
- Dirty Lenses: Dust or debris on the sensor lenses can weaken or block the beam. Cleaning the lenses with a soft cloth can solve this.
- Wiring Problems: Damaged or loose wiring can also cause sensor failure. Check the wiring connections and replace any damaged wires.
- Sunlight Interference: In rare cases, direct sunlight can interfere with the infrared beam. Shielding the sensors from direct sunlight may help.
Summary
Garage door sensors offer a simple yet highly effective safety system. By using an infrared beam to detect obstructions, they prevent the garage door from closing when the pathway is blocked, safeguarding people and property.
