Elevator Door Sensor: Light Curtain vs Photocell Guide
In This Article
An elevator door sensor helps detect passengers or objects in the doorway so the doors do not close on them. In busy apartments, offices, hospitals, and commercial buildings, door sensor performance directly affects passenger safety and comfort.
This guide explains how elevator door sensors work, the difference between light curtains and photocells, common fault signs, and when Dhaka building owners should call for service.
“Door sensors protect people during the most frequent elevator action: entering and exiting the cabin.”
— Sheikh Elevator World, 2026
What Is an Elevator Door Sensor?
An elevator door sensor is a detection device installed near the cabin doorway. It sends signals to the door controller when a person or object is in the closing path, causing the doors to reopen or remain open.
Older systems may use simple photocell beams, while newer elevators often use multi-beam light curtains. Light curtains give wider coverage and can detect smaller obstructions across more of the doorway.
If passengers complain that doors close too quickly or hit bags, check sensor alignment and door timing before accidents happen.
Signs of Door Sensor Problems
Door sensor faults can appear as doors reopening repeatedly, doors closing on passengers, or lift delays caused by false detection. Both safety and user experience suffer when sensors are dirty or misaligned.
- Doors close on people or objects
- Doors reopen repeatedly with no obstruction
- Sensor lens is dirty, scratched, or loose
- Door response is slow or inconsistent
- Fault appears more during dust, rain, or heavy traffic
Light Curtain vs Photocell
Light curtains and photocells both detect doorway obstruction, but they provide different coverage. Choosing the right system depends on lift age, passenger volume, and safety expectations.
| Item | What to check | Why it matters |
|---|---|---|
| Photocell | Single or limited beam detection | Basic protection but smaller coverage |
| Light curtain | Multiple infrared beams | Better coverage across doorway |
| Dirty sensor lens | False detection or missed obstruction | Cleaning may restore response |
| Misalignment | Beam does not connect correctly | Door may behave unpredictably |
Do not reduce door protection to stop nuisance reopening. Find the real cause: dust, alignment, wiring, or controller timing.
Maintaining Elevator Door Sensors
Door sensors should be cleaned and tested during regular elevator maintenance. Technicians should check alignment, wiring, response time, door speed, and controller settings.
Sheikh Elevator World can inspect door sensor faults, recommend replacement where needed, and support safer door operation for residential and commercial buildings.
Frequently Asked Questions
What does an elevator door sensor do?
An elevator door sensor detects people or objects in the doorway and signals the doors to reopen or stay open. It helps prevent door-closing accidents.
What is the difference between a light curtain and photocell?
A photocell usually uses one or a few beams, while a light curtain uses many beams across the doorway. Light curtains provide wider detection coverage.
Why do elevator doors keep reopening?
Repeated reopening may come from dirty sensors, misalignment, wiring faults, door timing issues, or actual obstruction in the doorway.
When should elevator door sensors be replaced?
Sensors may need replacement if they are damaged, unreliable after cleaning and alignment, or outdated for the building’s safety needs.
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