# Automatic Door Sensors: Infrared vs Microwave | GW GeWalt

> Microwave sensors trigger opening; infrared beams prevent clamping. Learn how each automatic door sensor works and which you need.

URL: https://gwgewalt.com/guide/automatic-sliding-door-sensor-types/
Last-Modified: 2026-07-10

# Automatic Sliding Door Sensors: Infrared vs Microwave

Microwave sensors trigger opening; infrared beams prevent clamping. Learn how each automatic door sensor works and which you need.

Published 10 July 2026 · 4 min read

![Sensor housing above an automatic sliding door in a Malaysian clinic](/images/featured/sensor-housing-mounted-above-an-automatic-sliding-.webp)

## Two Sensors, Two Different Jobs

Every quality automatic door runs at least two sensor types, and they do completely different jobs. Confusing them is the most common mistake we hear when owners describe a fault, so it is worth getting the split clear before you specify or troubleshoot anything on 

automatic sliding door systems

[/automatic-sliding-doors/ →](/automatic-sliding-doors/)

.

The **microwave motion sensor** is the activation sensor. Mounted above the door and angled outward, it emits a microwave field and reads the reflections; when a person moves through the field, the door opens. Microwave sensing detects motion at useful range, works day and night, and can be tuned for direction so the door ignores people walking past parallel to the entrance.

The **infrared safety beam** is the protection sensor. It watches the threshold itself — the space the leaves actually close through. While anyone or anything occupies that zone, the sensor holds the door open and vetoes the closing cycle entirely.

![Infrared beam zone across a door threshold](/images/content/diagram-style-view-of-infrared-safety-beam-zone-cr.webp)

## Activation vs Safety: Why Both Are Non-Negotiable

A door with only an activation sensor is a hazard: it opens for approaching traffic but has no idea whether someone slow — an elderly visitor, a wheelchair user, a delivery trolley — is still standing between the leaves when the close timer runs out. The infrared presence sensor closes that gap, and anti-clamp force monitoring in the controller backs it up as the last line of defence.

> **A quick self-test for your existing door**
> 
> Stand still in the middle of the open doorway for fifteen seconds. A healthy door stays open the whole time. If it tries to close on you, the presence sensor is misaligned, dirty or failed — book a service before it catches someone.

The two sensors also fail differently. Activation faults show up as a door that will not open or opens for nobody; safety-beam faults show up as a door that closes too eagerly. Describing which behaviour you see helps a technician arrive with the right part. Our guide on 

door safety features

[/guide/are-automatic-sliding-doors-safe/ →](/guide/are-automatic-sliding-doors-safe/)

 covers what the full protective stack looks like.

## Touchless and Special-Purpose Options

Beyond the standard pair, several activation options suit specific premises:

-   **Wave switches** — hold a hand near the plate and the door opens, no contact
-   **Foot sensors** — kick-to-open activation for staff carrying loads
-   **Push buttons** — controlled entry where the door should not open automatically
-   **Access-control integration** — card readers or intercoms trigger the opening cycle

Touchless options have become standard requests for clinics, laboratories and food premises, where hand contact on shared surfaces is the thing being designed out.

Sensor choice is part of every specification we prepare. Tell us your entrance, traffic pattern and any hygiene or security requirements, and we will match the activation and safety package to it — starting with an RM50 on-site measurement that is fully deductible from your order.

## Frequently Asked Questions

Which sensor opens the door?

A microwave motion sensor mounted above the door detects an approaching person's movement and triggers the opening cycle. It is the activation sensor, tuned for range and direction.

What stops the door closing on someone?

An infrared presence sensor or safety beam watches the threshold itself. While anyone stands in the opening, it holds the door open and blocks the closing cycle.

Can I get a touchless switch instead?

Yes. Wave-to-open switches and foot sensors trigger the door without contact, which suits clinics, food premises and other hygiene-sensitive sites.

## Learn more about Automatic Sliding Doors

See how we spec, supply and install automatic sliding doors — or send us your questions for a free quotation.

Automatic Sliding Doors

[/automatic-sliding-doors/ →](/automatic-sliding-doors/)

 

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