Hubbry Logo
Notification LEDNotification LEDMain
Open search
Notification LED
Community hub
Notification LED
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Notification LED
Notification LED
from Wikipedia
A notification LED on a smartphone

A Notification LED is a small RGB or monochrome LED light usually present on the front-facing screen bezel (display side) of smartphones and feature phones whose purpose is to blink or pulse to notify the phone user of missed calls, incoming SMS messages, notifications from other apps, low battery warning, etc., and optionally to facilitate locating the mobile phone in darkness.[1][2] It usually pulses in a continuous way to draw the attention of the user. It is a part of the device's notification system that uses a cloud-powered push notification service to relay remote notification messages to the user, or local notifications. Similar to audio notifications, a notification LED is a very battery-efficient way to inform the user of new notifications without turning on the screen at all.

Overview

[edit]

In any mobile phone or smartphone, battery life is an important consideration and the display is the component that consumes the maximum battery when it is fully lit up. In regular usage, a user may only want to briefly turn on their phone to check if anything requires attention.

By blinking unobtrusively, the notification LED light discreetly conveys to the user of any potentially important message or call.[3] This way, the whole display does not have to be turned on every time a message arrives, thus saving the battery. When the user is away from the phone or when the phone is in silent mode, the blinking LED can effectively convey the user that some action is needed. Conversely, if the light does not blink, then it conveys to the user that there is no unread message or notification that requires their attention, again saving battery and the user's time and effort required to unlock the device, and check for new messages.

In some phones, the LED notification light is also sometimes designed to glow red when the battery is low,[3] when the battery is charging and turn green when the battery is fully charged. This saves the user the hassle of turning on the screen to check the battery percentage.

While most phones used to include the notification LED light on the front side, some smartphone manufacturers like LG or Nokia also integrated it into the power button,[4] while some phones from Motorola, Xiaomi, Razer or ASUS had their brand logo on the back side of the phone, serving as the notification light.[5]

Depreciation

[edit]

Starting 2019 most smartphones vendors have stopped adding the notification LED which could be explained by the advent of AOD and a drive for smaller bezels.[6][7]

Customization based on app

[edit]

In some Android and BlackBerry smartphones, the notification LED light's behavior could be customized per app, so that, each color would indicate a different app. Apps like WhatsApp or Telegram also include a setting to set this color for the LED light.[1]

Alternative always on display feature

[edit]

The notification LED light was popular when feature phones were widely used. In early smartphones running Windows Mobile or the Android operating system, the LED notification light was also a fairly common feature. These smartphones usually had LCD screens, so without the LED present, the entire backlight behind the display would need to be turned on to check for any new notifications.

Gradually, the smartphone industry has been moving towards OLED displays. With this transition, the dedicated notification LED light has slowly been eliminated from newer smartphones. There is also a focus by smartphone designers to minimize the screen bezels or keep them very thin, thus leaving no room for the notification LED light.

As a replacement for the LED light, some smartphones from Samsung, LG, and Nokia include an Always On Display feature. On OLED displays, the Always-On Display (AOD) shows limited information while the phone is asleep, that is, when the entire display is not lit up. With OLED screens, only a part of the screen, or a few pixels on it can be turned on to convey information.

With any pixel on an OLED screen effectively being a notification LED, software can be used to customize its appearance. It can blink or pulse like a light continuously, or some phone manufacturers light up the display's pixels like a ring or have edge lighting.

Smartphones with Notification LEDs (since 2017)
Manufacturer Model Year LED Position LED Color Notes
Librem 5 2020 Front Top RGB
OnePlus 5 2017 Front Top RGB
OnePlus 5t 2017 Front Top RGB
OnePlus 6 2018 Front Top RGB Last OnePlus model with Notification LED
Samsung Galaxy J8 2018 ? ?
Sony Xperia 1 2019 Front Top RGB
Sony Xperia 1 II 2020 Front Top RGB
Sony Xperia 1 III 2021 Front Top RGB
Sony Xperia 1 IV 2022 Front Top RGB Last Xperia 1 series with Notification LED
Sony Xperia 5 2019 Front Top RGB
Sony Xperia 5 II 2020 Front Top RGB
Sony Xperia 5 III 2021 Front Top RGB
Sony Xperia 5 IV 2022 Front Top RGB Last Sony Xperia 5 series with Notification LED
Sony Xperia 10 2019 Front Top RGB
Sony Xperia 10 II 2020 Front Top RGB
Sony Xperia 10 III 2021 Front Top RGB
Sony Xperia 10 IV 2022 Front Top RGB Last Sony Xperia 10 series with Notification LED
Sony Xperia L3 2019 Front Top RGB
Sony Xperia XZ Premium 2017 Front Top RGB
Sony Xperia XZ1 2017 Front Top RGB
Sony Xperia XZ2 series 2018 Front Top RGB
Sony Xperia XZs 2017 Front Top RGB
Sony Xperia 8 2019 Front Top RGB
Sony Xperia L4 2020 Front Top RGB
Xiaomi Redmi Note 9 2020 Front Top ? Also on various related models
Xiaomi Redmi Note 7 2019 ? ?
Samsung Galaxy S8 series 2017 Front Top RGB
Samsung Galaxy S9 series 2018 Front Top RGB Last Samsung flagship smartphone with Notification LED
Samsung Galaxy Note 8 2017 Front Top RGB
Samsung Galaxy Note 9 2018 Front Top RGB Last Samsung phablet with Notification LED
BlackBerry Key1 2017 Front Top RGB
BlackBerry Key2 2018 Front Top RGB
BlackBerry Motion 2017 Front Top RGB
Oppo Reno 7 Pro 2021 Rear Top Blue
Motorola Moto G7 series 2019 Front Top RGB May need 3rd party S/W to enable. May be sub-model distinctions.
Motorola Moto Z3 2018 Front Top ? May need 3rd party S/W to enable.
Motorola Moto G5 series 2017 Front Top ? May need 3rd party S/W to enable. May be sub-model distinctions.
Nokia 3.2 2019 Side button White Overlaid with power button, white color only.
Nokia 4.2 2019 Side button White Overlaid with power button, white color only.
Xiaomi Redmi K50 2022 Rear ? Includes variants eg Poco F4 GT etc. Some are in camera module.
ASUS Zenfone 8 2021 Bottom Edge Simple color Reputedly only supports red, green and yellow
Xiaomi Mi 10T Pro 2020 Front, Top Left White
Huawei Y6 (2018) 2018 Front, Top Left RGB The phone uses Red, White, and Green (follows battery level) for generic notifications. Otherwise, the phone follows the LED color that the app uses.

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
A notification LED is a small (LED) typically embedded in the front or display area of smartphones, feature phones, and other mobile devices, designed to provide discreet visual alerts for events such as incoming calls, messages, emails, low battery, or charging status by blinking or steadily glowing in specific colors. These LEDs, often RGB-capable for multicolored output, allow users to recognize notification types at a glance without activating the screen, conserving battery life and enabling visibility from a distance. Common color codes include blue for general notifications or pulsing during power states, for charging or unread alerts, and for full charge completion, with app-specific customizations possible on supported devices. The feature originated in early mobile phones from the , evolving through the era as a battery-efficient alert method, and saw peak adoption in early smartphones before declining in flagships due to design changes like slimmer bezels and notches. As of 2025, notification LEDs persist in some mid-range Android phones from manufacturers like and , valued for by reducing the need to unlock devices—users check phones around 150 times daily on average—while providing brighter feedback than always-on display alternatives.

Definition and Functionality

Purpose and Benefits

A notification LED is a small (LED), typically RGB-capable or monochrome, positioned on the front or edge of mobile devices such as smartphones and feature phones, designed to blink, pulse, or glow in response to various alerts. This feature provides a subtle visual indicator without requiring the device to activate its main display or emit sound. The primary purposes of a notification LED include alerting users to incoming or pending events, such as missed calls, text messages (), app notifications from services like or , low battery levels, and charging status. For instance, it may emit a steady blink for missed calls, an intermittent for new messages, or color-coded signals during charging—such as for low battery or ongoing charge, green for full charge, and blue for other app-specific alerts. These functions enable users to stay informed about device activity at a glance, particularly in silent or do-not-disturb modes. Key benefits of the notification LED encompass its energy efficiency, as the LED consumes far less power than illuminating the full screen or activating an , thereby preserving battery life during idle periods. It delivers discreet, non-intrusive notifications that are visible from a distance, allowing users to detect alerts without interacting with the device or disrupting their surroundings. Additionally, it enhances for users with hearing impairments by providing a reliable visual cue for sounds they may not hear, such as incoming calls or alarms, promoting greater independence and safety.

Operational Mechanism

The notification LED operates through a of dedicated hardware and software within the smartphone's operating , enabling low-power visual signaling for incoming events. At the hardware level, the notification LED is usually implemented as a compact tri-color RGB LED or a simpler variant positioned in the device's front near the display. This LED is powered directly from the phone's battery via the power management (PMIC), drawing minimal current—typically in the range of 1-20 mA per color channel depending on brightness and —to ensure negligible impact on overall battery life. The LED is driven by a dedicated controller or the main SoC's GPIO pins, which modulate the output using (PWM) techniques to achieve blinking patterns by varying the on/off durations for each color channel. On the software side, the mechanism is triggered when the operating system receives a notification intent from an app or system event, such as an incoming call or message. In Android, this is handled primarily through the NotificationManager service, where developers or the system can invoke the setLights method on a NotificationCompat.Builder to specify the LED color (via ARGB value), on duration (in milliseconds), and off duration (in milliseconds), creating a repeating blink cycle until the notification is acknowledged or times out. For Android 8.0 () and later, LED behavior is managed at the notification channel level, allowing users to enable or customize lights per category in system settings, while the OS checks user preferences before activating the driver. In older iOS models supporting equivalent features (such as LED flash alerts introduced in ), a similar process uses the rear camera flash LED, controlled via accessibility settings to pulse in response to events when the device is locked or silent. The activation sequence begins with the OS intercepting the event, validating against user-configured settings (e.g., enabling LED notifications globally or per app type), and then signaling the LED driver IC to apply the specified color and pattern—commonly for calls, for messages, or white for general alerts—persisting for a configurable timeout period of 10-30 minutes or until dismissed. Integration with other device features ensures contextual behavior; for instance, the LED pauses during active calls via linkage to the , which detects when the phone is held to the ear, and is suppressed entirely in Do Not Disturb mode to respect user silence preferences. Regarding power efficiency, the notification LED's pulsing operation consumes significantly less than alternatives like screen wake-ups, with estimates indicating less than 0.1% battery drain over an hour of continuous blinking on a typical 3000 mAh battery, due to its low current draw and intermittent . This prioritizes always-on visibility without substantial resource overhead, leveraging the LED's direct battery connection and PWM for precise, efficient control.

History and Adoption

Early Implementations

The origins of notification LEDs trace back to the early in feature phones and personal digital assistants (PDAs), where they served as compact, low-power visual indicators for basic alerts like incoming calls or messages. One of the earliest notable implementations appeared in devices like the SCP-5500, released in 2004, which featured a customizable notification light supporting up to six colors for different , marking a shift toward more versatile signaling in clamshell phones. Similarly, the (2004) included an external LED indicator that flashed to denote connectivity and charging status, evolving from simple power lights to rudimentary notification functions in flip phone designs. These early LEDs were driven by the demand for battery-efficient alerts in increasingly portable devices, allowing users to receive signals without activating the screen or relying solely on audible tones. In parallel, devices pioneered pulsing LED notifications during this period, providing discreet visual cues for and message arrivals in enterprise-focused PDAs. Earlier models like the 850, launched in 1999, featured a basic LED for unread message alerts. The Pearl 8100, launched in 2006, integrated a multi-color notification LED in the top-right corner, enabling basic customization for alerts such as new messages or , which enhanced usability in silent environments. This adoption was further influenced by growing emphasis on accessibility in the , as visual indicators like LEDs complemented vibrating alerts to support users with hearing impairments, aligning with emerging standards for inclusive mobile technology. Regulatory developments, such as the U.S. Access Board’s Section 508 standards finalized in 2000, encouraged accessible features in electronic devices, indirectly promoting visual signaling in . Early smartphone platforms extended this functionality, with Windows Mobile devices like the HTC Wizard (2005) incorporating LED indicators primarily for status and camera flash, though limited to basic on/off signaling. The debut of Android in 2008 with the (also known as the T-Mobile G1) marked a key milestone, featuring a dedicated notification LED near the earpiece that blinked to signal new messages or events, transitioning toward more standardized integration in smartphones. However, these initial versions were constrained by hardware limitations, typically offering only or single-color output with fixed blinking patterns, and lacking app-specific controls due to the era's rudimentary software ecosystems.

Peak Usage in Smartphones

During the , notification LEDs reached their zenith in popularity within the Android ecosystem, becoming a ubiquitous feature in smartphones from 2010 to 2018, offering users a subtle, at-a-glance way to monitor alerts without unlocking the device. integrated RGB notification LEDs into its Galaxy S series up to the Galaxy S9 released in 2018, enabling multi-app differentiation through customizable colors for various notifications such as messages, calls, and system events. Similarly, HTC's One series throughout the decade featured a prominent front-facing LED, positioned above the display for enhanced visibility in pocket or bag use, which allowed for distinct blinking patterns to indicate different types of alerts. While adoption was more restrained on , Apple repurposed the rear camera flash as a notification light in models from the through the , providing a simple pulsing effect for incoming alerts starting with iOS updates in the early . maintained strong support for the feature in its Xperia lineup, including the XZ Premium in 2017, where the LED supported multiple colors for app-specific notifications. also embraced it in devices up to the in 2018, integrating the LED into the alert system for quick status checks. These implementations were facilitated by the era's trends, such as larger bezels that accommodated the hardware without compromising . Feature enhancements during this period elevated the utility of notification LEDs, with many devices employing RGB setups capable of displaying up to 16 million colors to encode detailed information like app origins or priority levels. Some models integrated the LED with advanced network features, such as VoLTE, to flash specific patterns for incoming voice calls over LTE connections. By 2015, the feature had permeated mid-range Android phones, appearing in a majority of models to meet consumer demand for practical battery-saving notifications. Tech reviews from 2012 to 2018 frequently lauded the LED's convenience, highlighting its role in reducing screen wake-ups and improving user experience in daily scenarios like meetings or sleep. The final major implementations of traditional notification LEDs appeared in select flagships up to 2022, including Sony's Xperia 1 IV, which retained the multi-color front LED for alerts. These devices marked the tail end of widespread adoption before manufacturers shifted priorities.

Customization Options

App-Specific Settings

In Android devices equipped with a notification LED, users configure app-specific settings through the system's notification management interface, typically accessed via Settings > Notifications > App notifications. Here, individual apps such as or can be selected, and options like notification importance can be set to high priority, enabling the LED to upon receiving alerts from that app if the hardware supports it. This process relies on Android's notification channels, introduced in Android 8.0, which allow developers to categorize notifications (e.g., messages versus updates) and users to toggle LED triggering per category without affecting the entire app. BlackBerry OS offered native LED control for certain system events through the device's hub, but comprehensive per-app customization typically required third-party applications such as BeBuzz or HUB++. On devices, the rear camera flash LED for alerts is limited to system-wide activation for built-in apps like Phone or Messages, configured via Settings > > Audio/Visual > LED Flash for Alerts; per-app customization is not natively available. For greater granularity, Android's system supports assigning LED activation per app category, such as distinguishing notifications from , by adjusting channel importance levels—high-importance channels prioritize LED use over low ones. In cases of multiple simultaneous notifications, the OS employs priority queuing, where higher-priority alerts (e.g., from starred contacts) take precedence, potentially cycling the LED through active notifications to indicate ongoing activity. Manufacturer variations, like Samsung's , enhance this by allowing app grouping in notification settings for improved notification management. Third-party apps, such as Light Flow (introduced in the early 2010s), extend native capabilities on Android by providing finer per-app LED control, including toggling activation for over 600 apps and handling priority queuing; these require granting notification access permission to function. Limitations include inconsistent native support across apps, as not all developers implement notification channels that trigger the LED, and functionality varies by manufacturer— for instance, some devices lack hardware LEDs altogether, rendering settings ineffective.

Color and Pattern Customization

Notification LEDs on smartphones, particularly those equipped with RGB capabilities, enable users to customize colors for distinguishing between different types of alerts, with many devices supporting over 16 distinct hues through , , and blue light combinations. For instance, a blue light might indicate a notification, while could signal an incoming call or low battery status. In contrast, monochrome LEDs are restricted to simple on/off pulsing without color variation, limiting their utility for nuanced signaling. Pattern customization further enhances distinguishability by adjusting blink rates and durations to convey priority levels. Slow blinking, such as extended intervals between pulses, is often used for low-priority notifications, whereas fast blinking—perceived as more urgent and effective by users—alerts to high-priority events like missed calls. Typical cycles include various on/off durations, with options for steady illumination or advanced Morse-like codes in supported applications. Stock Android implementations offer limited customization, primarily allowing users to enable or disable the LED without color or pattern adjustments. Third-party apps expand these options significantly; for example, LED Blinker Notifications permits per-app color selection, adjustable blink speeds, and pattern variations, including support for gradients and animations. Similarly, Light Manager enables configuration of LED colors, flash frequencies, and durations for specific apps or events. Manufacturer-specific features provide tailored presets prior to hardware deprecation around 2019. devices, such as those in the S series up to the S9, featured predefined colors like for device power states, for charging or notifications, and green for full charge, with basic pulsing patterns. Sony's Xperia series, including models like the SP, utilized apps such as Discolight or official APIs for individual RGB control of the illumination bar, allowing custom colors and synchronized pulse patterns. Advanced features in customization apps include synchronization of LED patterns with device vibrations for multimodal alerts and adjustable timeouts ranging from 5 to 60 minutes to control how long the light persists after a notification. These options, often requiring notification access permissions, help users tailor the LED to personal preferences while integrating with app-specific triggers.

Decline and Alternatives

Reasons for Deprecation

The shift toward bezel-less screen designs in flagship smartphones, beginning prominently with models like the in 2017 and the Galaxy S10 in 2019, significantly reduced available space on the front fascia for dedicated notification LEDs, as manufacturers prioritized maximizing display area to meet consumer demand for immersive viewing experiences. These designs eliminated the traditional placement for front-facing LEDs, forcing trade-offs in hardware features to achieve slimmer profiles and higher screen-to-body ratios exceeding 90%. Additionally, the pursuit of water-resistant certifications, such as IP68 ratings standard in flagships since around 2016, introduced integration challenges for LEDs, requiring complex sealing to prevent water ingress while maintaining functionality, which increased design complexity without proportional benefits. Technological advancements in display technology further diminished the necessity of separate notification hardware, with the rise of and panels enabling efficient (AOD) features that could render persistent notifications directly on the screen. The Moto X introduced an early form of always-on notifications with Active Display in 2013, while Samsung's Galaxy S7 (2016) popularized full AOD on consumer smartphones, allowing low-power visibility of time, date, and alerts without full screen activation. By 2018, AOD became widespread in Android flagships like the , leveraging the per-pixel lighting control of to minimize power draw—typically under 1% additional battery usage per hour—compared to the negligible but dedicated consumption of a standalone LED. This integration rendered physical LEDs redundant, as screen-based notifications offered greater flexibility for detailed alerts without extra components. From a practical standpoint, notification LEDs provided only marginal battery savings relative to AOD—often less than 0.1% per notification cycle—while adding to expenses in increasingly slim devices, where even small hardware elements contributed to overall production costs. While some users miss notification LEDs, others have adapted to screen-based alternatives, as discussed in tech reviews and forums. Major manufacturers actively phased out notification LEDs in response to these trends, with omitting them starting from the Galaxy S10 lineup in 2019 to streamline the bezel-less aesthetic, a decision echoed across their subsequent models. Apple never widely incorporated front-facing notification LEDs in iPhones, relying instead on screen and sounds from the outset. Sony removed the feature starting with the Xperia 1 V in 2023; LG's last , the V60 (2020), included it, but the company exited the smartphone market in 2021. As of 2025, notification LEDs are rare in new releases but appear in some and niche models from brands like and , though no precise adoption rate is available. On the environmental and user fronts, eliminating dedicated LEDs contributed to reduced through simpler device architectures, avoiding components prone to failure over time, such as LED degradation or after prolonged use spanning several years. User reports frequently highlighted concerns, including dimming or inconsistent performance in older devices, further justifying the shift to more reliable integrated display solutions.

Modern Replacement Technologies

With the deprecation of physical notification LEDs in most smartphones, manufacturers have shifted to screen-based technologies that leverage modern and displays for low-power visual alerts. One prominent replacement is the (AOD), a feature that keeps essential information like time, date, battery status, and notification icons visible on the without fully activating the device. first introduced AOD on its S7 and S7 edge smartphones in 2016, utilizing the energy-efficient properties of AMOLED panels to illuminate only specific pixels, resulting in minimal battery consumption—typically adding less than 1% drain over 24 hours under normal usage conditions. integrated a similar AOD capability into its lineup starting with the in 2018, evolving it to include dynamic elements like music controls and updates while maintaining low power draw through adaptive refresh rates. Building on AOD, edge lighting and animated notifications provide more engaging visual cues by utilizing the curved or full-screen edges of devices. Samsung's Edge Lighting, initially launched with the S6 edge in 2015 and refined in subsequent models from 2017 onward, pulses colorful light effects around the screen's perimeter or camera cutout upon receiving alerts, customizable by app and allowing for patterns that mimic LED behaviors without dedicated hardware. Apple's Dynamic Island, debuted on the in 2022, transforms the front camera pill-shaped cutout into an interactive notification hub that expands with haptic feedback and animations for calls, music, or messages, offering a seamless blend of visual and tactile alerts that enhance user interaction beyond simple color blinking. These features improve upon LEDs by supporting richer content like icons or live previews, though they may consume slightly more power during active pulses compared to a static LED. In iOS, users can enable screen flash for alerts via Settings > Accessibility > Audio/Visual by turning on Flash for Alerts, which provides options for screen flashing or combining it with LED flash. This feature is particularly useful in dark environments or silent mode, serving as a modern alternative to traditional notification LEDs. Additionally, brands like have introduced the Glyph interface, featuring rear LED strips for animated notifications on models such as the Phone (3a) Lite (2025), offering a hardware-based alternative to traditional front LEDs. For devices lacking native hardware, third-party software simulations replicate LED effects using available components. Apps such as LED Me Know, available since the early and updated for through 13, repurpose the screen's edge pixels or rear camera flash to display customizable blinking animations for incoming notifications, enabling LED-like persistence on models like the S21 series without physical lights. Complementary Android features include Ambient Display, which briefly wakes the screen to show notifications upon detection of motion or new alerts, and notification history introduced in in 2020, allowing users to review dismissed or missed alerts via a dedicated log for up to 24 hours. Additionally, integrations with wearables like smartwatches provide vibration-based notifications synced to the phone, reducing reliance on visual cues altogether while ensuring discreet alerts during meetings or sleep. These modern technologies offer distinct advantages over traditional LEDs, including greater customization through full-color icons, text previews, and animations rather than limited color coding, as well as superior in bright environments due to higher screen . However, they can incur higher power usage in non-optimized scenarios, though advancements in display tech have mitigated this to levels comparable to or better than LEDs in daily use. As of 2025, AOD and similar features are widely standard in flagship smartphones from major vendors like , , and Apple, reflecting widespread adoption driven by bezel-minimizing designs.

References

Add your contribution
Related Hubs
User Avatar
No comments yet.