Introduction
Light-emitting diodes (LEDs) are everywhere, from tiny indicators on gadgets to massive outdoor displays. These semiconductor devices emit light when an electric current passes through them.
In embedded systems, LEDs serve as essential components, often used as status indicators. No embedded project feels complete without at least one LED, in fact “Hello, World” of embedded systems is blinking an LED.
There are many types of LED lights, each designed for specific applications. Choosing the right LED based on power consumption, brightness, and technical specifications ensures optimal performance and prevents damage. Understanding the different types of LED lights can help create efficient and reliable embedded projects.
Types of LED Lights, Consumptions & Applications
Standard Indicator LEDs
These LEDs commonly serve as status indicators in electronics. They come in different diameters, such as 3mm and 5mm, with a through-hole design. They typically draw 20-30mA of current at a forward voltage of 2-3.3V, though the exact value depends on the LED’s color and diameter. For example, blue and white LEDs consume more power than red or green ones.
Common colors include red, green, blue, yellow, and white, along with multicolor options like RGB LEDs. Their brightness levels vary from 2 to 10+ lumens, depending on the color. For instance, red and green LEDs appear brighter than others.
Applications:
Manufacturers use them as power and signal indicators in consumer electronics, including small gadgets, toys, and household appliances. Additionally, they appear in dashboard indicators and sometimes serve interior lighting purposes.
SMD LEDs
Surface-Mount Device (SMD) LEDs offer a compact, high-efficiency lighting solution designed for direct surface mounting on printed circuit boards (PCBs). Unlike traditional through-hole LEDs, manufacturers solder them directly onto the board, making them ideal for modern electronics and miniaturized devices.
These LEDs come in various sizes, with common ones being 3528, 5050, and 2835, where the numbers indicate dimensions in tenths of millimeters (e.g., 3528 measures 3.5mm × 2.8mm). Their power consumption ranges from 10-150mA, depending on size and brightness, with a forward voltage of 2-3.3V—similar to Standard LEDs. Their brightness varies from 4 lumens for small SMDs to 100 lumens for high-powered versions.
Common colors include red, green, blue, yellow, and white, along with multicolor options like RGB, RGBW, which frequently appear in microcontroller boards.
Applications:
SMD LEDs are widely used in backlighting for LCDs and keypads, automotive lighting, and LED strips for decorative and functional lighting. In embedded systems, they are preferred for status indicators, illuminated buttons, and display backlights due to their efficient power consumption and easy integration with microcontrollers.
High-Power LEDs
High-power LEDs provide significantly greater brightness than standard indicator or SMD LEDs. They consume between 350mA to several Amps, depending on wattage, with a voltage rating ranging from 3V to 12V. Their brightness varies widely, from 100 lumens to several thousand lumens, based on type and power rating. These LEDs come in various wattages, starting from 1W and extending up to 100W for LED arrays/modules.
Manufacturers offer them in multiple colors, including white, warm white, cool white, red, green, blue, and RGB variants, making them ideal for both functional and decorative lighting applications. With increased energy output, these LEDs feature enhanced heat dissipation mechanisms to handle the additional heat they generate, ensuring durability and efficiency in high-performance applications.
Applications:
High-power LEDs serve in automotive headlights, street lighting, industrial lighting, stage lighting, and high-intensity flashlights. They play a key role in medical devices, horticulture lighting (for plant growth), and smart lighting systems. In embedded projects, they function as powerful visual indicators and high-intensity signaling systems, where brightness and efficiency are crucial.
OLEDs
Organic Light-Emitting Diodes (OLEDs) use organic compounds to emit light when an electric current passes through them. Unlike traditional LEDs, they do not need a backlight since each pixel produces its own light. This feature allows for thinner, more flexible, and energy-efficient displays with superior contrast and deeper blacks.
OLEDs operate at lower voltages than traditional LEDs, typically ranging from 2V to 12V, depending on display size and color. Their power consumption varies based on displayed content—darker images consume less power since black pixels remain off. Brightness levels range from 100 to over 1000 nits, making OLEDs ideal for high-contrast, vibrant displays.
Types of OLEDs:
- Passive Matrix OLEDs (PMOLEDs) – Suitable for smaller displays like wearables and embedded projects. They offer power efficiency but have limited resolution.
- Active Matrix OLEDs (AMOLEDs) – Used in high-resolution displays like smartphones and TVs, providing better refresh rates and power efficiency.
- Flexible OLEDs – Appear in foldable smartphones, curved monitors, and rollable displays.
- Transparent OLEDs – Enable futuristic, see-through displays.
Applications:
OLEDs enhance smartphone screens, television displays, smartwatches, and VR headsets by offering a thin design, deep contrast, and flexibility. They serve embedded systems by delivering compact, high-quality graphical interfaces that require low power consumption and high visibility. Due to their self-emitting nature, OLEDs work well in battery-operated devices, automotive dashboards, and advanced wearable technologies.
Addressable LED Strips
These versatile LEDs allow individual control using a digital signal. Integrated driver chips enable dynamic effects, animations, and color transitions. Most strips operate at 5V or 12V, while high-power variants require up to 24V. Their power consumption depends on LED density and brightness, typically ranging from 0.3W to 1W per LED. Brightness varies based on the LED type, with high-density strips reaching over 1000 lumens per meter.
One popular example is the WS2812B RGB LED strip, which operates at 5V and includes an integrated WS2812 driver chip, allowing control via a single data line.
Applications:
These LED strips enhance decorative lighting, smart home systems, and interactive displays. Microcontrollers like Arduino, ESP32, and Raspberry Pi control each LED individually, creating custom visual indicators for various systems. Additionally, addressable LEDs play a key role in wearable tech, robotics, and IoT devices, boosting both aesthetics and functionality.
Seven-Segment LEDs
These numeric display modules show digits and limited alphanumeric characters. A seven-segment display consists of seven individual LED segments (labeled ‘a’ to ‘g’) and a dot, arranged in a figure-eight pattern. By selectively illuminating segments, it displays numbers (0-9) and some letters (A-F). These displays operate at 3V to 12V, with each segment drawing 10-20mA of current. Power consumption depends on the number of segments lit at a time, while brightness ranges from 5 to 50 lumens, based on the LED type. High-efficiency versions use low-power LEDs to reduce energy consumption in battery-operated devices.
Types of Seven-Segment Displays
- Common Anode (CA) – All segments share a common positive (anode) pin, and individual segments turn on by grounding their cathodes.
- Common Cathode (CC) – All segments share a common negative (cathode) pin, and individual segments illuminate when voltage applies to their anodes.
- Multi-Digit Displays – Available in 2-digit, 4-digit, and 8-digit configurations, often controlled using multiplexing circuits for efficiency.
- Alphanumeric Variants – Some models feature 14-segment and 16-segment versions, allowing letter display in addition to numbers.
Applications:
Seven-segment displays play a crucial role in digital clocks, timers, calculators, scoreboards, and fuel station meters. In embedded systems, they provide a simple, cost-effective way to display numerical data efficiently. When controlled via microcontrollers like Arduino, PIC, and ESP32, these displays show real-time readings, dynamic values, and interactive outputs.
Conclusion
While there are numerous types of LEDs available, we have focused on those that are most useful in developing effective embedded systems projects. From standard indicator LEDs to advanced seven-segment displays, each type serves a specific purpose, enhancing both functionality and user interaction. Whether for status indication, illumination, or dynamic visual feedback, selecting the right LED is crucial for optimizing power consumption, performance, and overall system efficiency.
References
All information in this article has been referenced from the Wikipedia page on LEDs and other external sources, which provide detailed insights on LED types, power consumption, and applications. For more details on different types of LED lights, visit: Lin
