How do smart glasses work? Display, cameras, sensors, pairing, apps.

How "they work" depends on the type.

When people ask how do smart glasses work, they're often talking about very different products.

• Audio glasses focus on calls, music, and voice assistants.
• Camera glasses focus on capture (photos/video) and quick sharing.
• Display glasses focus on showing glanceable info (often text) in your field of view.
• "Virtual screen" AR glasses focus on showing a large external display from a phone or laptop, usually through a video cable.

If you're comparing smart glasses for work or travel, the most important thing to understand is where the work happens: on the frames, on your phone, or in the cloud. For a feature-by-feature overview (instead of the tech), see what smart glasses can do. For category definitions, start with the types of smart glasses.

How we evaluated this.

• We used the most common consumer architecture (glasses + phone + optional cloud) as the baseline.
• Cross-checked connectivity details against official standards documentation.
• Used Even G2 as a real example of a display-first design (no camera, no speaker).

The smart glasses tech stack (inputs → processing → outputs).

Inputs (what the glasses can sense).

Most smart glasses have a mix of:

• Microphones (voice commands, calls, captions/transcription)
• Buttons or touch surfaces (tap, swipe, long-press)
• Sensors (motion, ambient light, proximity/wear detection)
• Cameras (model-dependent)

Processing (where the "smart" happens).

Smart glasses rarely do everything on the frames. A typical split looks like this:

The practical takeaway: even when the display is "on your face," the phone is often doing the heavy lifting (and supplying the internet connection).

Outputs (what you get back).

Depending on the model, outputs can include:

• Visual overlays (a HUD-style display or a "virtual screen")
• Audio (open-ear speakers in the frame, earbuds, or none)
• Haptics/alerts (often through your phone or a paired accessory)

How smart glasses displays work (HUD vs "virtual screen").

HUD text overlays (microdisplay + optics).

In display-first smart glasses, a tiny microdisplay or projector creates an image. Optics then route that image into your line of sight so it appears as a floating overlay. Many everyday pairs prioritize:

• Text-first UI (readable in more conditions, with less visual clutter)
• Limited graphics (icons, short prompts, simple navigation cues)
• High contrast colors (because this is about legibility, not cinema)

Example (display-first, privacy-forward): Even G2 is built around a floating display for visual info like notes, translation, and navigation prompts. It uses a monochromatic green display for contrast, with a 640×400 px panel that can show 7+ lines of text. Hardware choices support all-day wear: titanium temples, a magnesium frame with a sandstone-fused coating, screwless hinges tested to 100,000+ cycles, and water/dust resistance. Even G2 also omits cameras and speakers, which can make day-to-day use easier in offices and other "no recording" environments.

If you're comparing HUD styles, brightness tradeoffs, monocular vs binocular layouts, and what the overlays look like, see our guide to smart glasses with display.

Virtual screen" AR glasses (video-in display).

"Virtual screen" glasses are closer to a wearable monitor than a HUD. Instead of rendering small widgets, they show video output from another device (phone, laptop, handheld console). Many rely on USB‑C for video and power, which is why compatibility often comes down to whether your device supports video over USB‑C.

Cameras in smart glasses (and what "recording indicators" really mean).

The capture pipeline (high level).

When smart glasses include a camera, the workflow usually looks like:

1. Lens + image sensor capture light
2. On-device processing handles encoding (and sometimes stabilization)
3. Storage lands on the glasses, the phone, or both
4. Sharing happens through the companion app

Recording tends to increase heat and battery drain because video capture is continuous.

Privacy indicators (high level).

Most camera glasses include some combination of:

• An external LED
• A sound cue
• An on-screen/app indicator

Details vary by model, and social norms vary by setting. If you need the deeper breakdown—what models can do, how indicators work, and etiquette—read our guide on whether smart glasses can take pictures or record video.

Sensors & MEMS (motion, auto-brightness, and "presence detection").

Most sensors in smart glasses are MEMS components (micro‑electro‑mechanical systems), which is why they can be small and low-power.

IMU motion tracking (accelerometer + gyroscope).

An IMU helps the glasses understand orientation and motion. Common uses include:

• Wake/sleep behavior (model-dependent)
• Basic head-motion interaction (for selection or UI navigation)
• Improving stability for camera capture (model-dependent)

Light/proximity sensors.

Depending on the design, these can support:

• Auto brightness for displays
• Wear detection (glasses on/off your face)
• Screen wake when you look up (model-dependent)

Detecting presence from far away".

Long-range "presence detection" usually implies cameras + computer vision (and sometimes depth sensors). Many everyday smart glasses don't do this at all—especially camera-free designs.

Pairing and connectivity (Bluetooth, Wi‑Fi, and phone dependence).

How Bluetooth pairing works in practice.

Most smart glasses pair to a phone over Bluetooth (often using Bluetooth Low Energy for parts of the connection). The typical setup flow is:

1. Put the glasses in pairing mode
2. Pair in the companion app (and sometimes in the phone's Bluetooth menu)
3. Approve permissions (notifications, microphone, contacts—depends on features)
4. Choose what gets mirrored or shown on the display

If pairing fails, it's often one of three reasons: low battery, Bluetooth already connected to another device, or a missed permission prompt.

Do smart glasses need Wi‑Fi?

Many don't need Wi‑Fi on the glasses themselves. Instead:

• The phone provides internet (cellular/Wi‑Fi) for cloud features.
• The glasses use Bluetooth for commands and data exchange.
• Some models add Wi‑Fi for faster updates or specific features, but this is not universal.

What phones do smart glasses work with (iOS vs Android).

Compatibility usually comes down to:

• Is there a companion app for your OS?
• Does your OS version meet the app's minimum requirement?
• Can you grant notification and microphone permissions?
• Do you need any extra permissions for background operation?

Some features can differ between iOS and Android systems because permission models and background limits differ.

Companion apps and "can smart glasses run apps?"

A companion app is often the real control center for smart glasses. It typically manages:

• Setup and device pairing
• Firmware updates
• Notification filtering
• Display layouts/widgets (calendar, weather, notes, navigation prompts)
• Privacy settings (where applicable)

Even G2 uses Even OS on the glasses, with the Even Realities App for setup, updates, and choosing what shows up in the display (including features like Teleprompt, Translate, and meeting-focused tools like Conversate).

Do Android apps work on smart glasses?

Usually not in the "open any app on the lens" sense. You'll typically see one of these patterns:

1. Notification mirroring (you see alerts and snippets)
2. Vendor widgets/mini experiences (built by the glasses maker)
3. Virtual screen mirroring (for video-in glasses, the phone/laptop runs the apps)

Power Apps / Anki.

Most smart glasses won't run Power Apps or Anki natively. Practical workarounds are usually:

• Push key items via notifications
• Using a notes widget or a web-based view (if supported)
• Control content from the phone while the glasses show prompts

How people interact with smart glasses (voice, touch, rings, cursor).

Voice and speech recognition (and captions).

For captions or transcription, the flow is often:

• Microphones capture speech → speech-to-text runs on the phone or cloud → text renders on the display

Noisy rooms, overlapping speakers, and accents can impact accuracy. For attention and situational awareness tips, see smart glasses safety considerations.

Touch/buttons vs external controllers.

Controls vary by model:

• Touch or button controls on the temple
• Voice commands
• External controllers (rings, wrist band, gesture devices)

Even R1 Ring is an example of a discreet controller designed for scrolling and selecting without touching the frame. It also supports health tracking (heart rate, HRV, SpO₂, sleep stages) and offers a daily "Productivity Score".

Moving a cursor" on smart glasses.

Cursor control (when it exists) is usually one of these:

• Head-aim + confirm gesture
• Touchpad-style input on the temple
• Ring-based directional input
• Eye tracking (model-dependent and not usually found in everyday eyewear)

Battery, charging, and turning smart glasses on/off.

Why battery life varies so much between models.

Battery draw depends on what's active:

• Display brightness and refresh behavior
• Always-on microphones
• Recording (for camera glasses)
• Wi‑Fi/cellular use through the phone for cloud features

Charging methods you'll see.

Common approaches include:

• USB‑C
• Magnetic or pogo-pin contacts
• Charging cases (model-dependent)

Quick power checklist.

• If the glasses won't turn on: charge for 15–30 minutes, then try a long-press power cycle.
• If features don't show up: confirm the companion app has notification/microphone permissions and check for firmware updates.
• If behavior is erratic: restart both the glasses and the phone, then re-open the companion app.

Conclusion.

Smart glasses aren't a single device that does everything—they're usually a system shared between the frames, your phone, and sometimes cloud services. Once you know whether you want a HUD overlay, a camera, audio, or a virtual screen, the rest of the "how it works" becomes much easier to anticipate.

FAQ.