Smart LEDs, also known as addressable LEDs, are a newer development in the world of optoelectronics. Smart LEDs are most commonly RGB LEDs with an integrated driver that accepts data in some form. The data format often varies based on the internal LED driver. These LEDs are often advertised as products such as neopixels, addressable, or by their driver’s part number. These LEDs allow the user to use a small number of IO pins, often 1 or 2, to push new data out to the LED drivers.
An addressable LED strip
- Use fewer IO pins. These addressable LEDs often require just 1 or 2 IO pins to control an entire array of LEDs. This allows the user to control numerous LEDs without separate drivers or many IO pins.
- Fewer discrete parts. With addressable LEDs, few external components are typically needed. With a normal RGB LED, resistors, transistors, and/or discrete drivers may be needed.
- Cost. Addressable LEDs are often more expensive than normal RGB LEDs.
- Software complexity. Addressable LEDs change the hardware complexity to software complexity.
- Availability. Addressable LEDs may not have the longest product availability life. Currently they are distributed by companies that are more geared towards hobbyists rather than manufacturers.
Addressable LEDs are sold in various formats such as strips and discrete LEDs. Different addressable LEDs are most often identified based on the driver that they implement. Below are some of the more popular options.
WS2812s are most likely the most popular addressable LEDs with hobbyists at the present. These LEDs use a one-wire interface with relatively precise timing requirements. These are also sold by Adafruit's Neopixels. The WS2812 is commonly found in a surface mount 5050 sized package, although there are other packages available, such as 8mm through hole variants.
The APA102 addressable LEDs are another popular option. These LEDs use a two-wire interface consisting of a data line and a clock line. Due to the extra clock line, highly accurate timing is not needed, in contrast to the WS2812 LEDs. These are sold by Adafruit under the name Dotstar.
Potential applications for addressable LEDs vary. The intended application for these are large LED displays such as outdoor billboards and Jumbotrons as well as interior and exterior dynamic accent lighting. However, since these have been introduced for use in the hobbyist market they've been used in applications such as lights on robots, holiday decorations, and wearable projects. The hardware simplicity of these LEDs has added to their popularity.
With addressable LEDs becoming increasingly popular and very inexpensive, it's a great time to pick some up and experiment. What are you going to make?