If you look at a data sheet for WS2812B RGB LEDs (commonly known as NeoPixels), you’ll see that they need an input voltage of between 3.5 V and 5.3 V, and a signal voltage of at least 0.7*input voltage. The vast majority of microcontrollers now on the market operate at 3.3V, with additional voltage outputs of 5 V and 3.3 V. This causes a problem because it means that there’s no way to connect NeoPixels directly to the microcontroller without going
out of these ranges. If you connect the NeoPixels to the 5 V power, then they need at least 3.5 V to operate, which is more than the microcontroller’s data pins output.
Of course, just because a data sheet says that they need at least 0.7*input voltage, it doesn’t mean that they do. Many people connect NeoPixels up directly to 3.3 V microcontrollers without problems. Here at HackSpace magazine, we’ve been wondering what we should advise people to do – follow the data sheet even though that leads to more complexity, or ignore the data sheet and cross our fingers as many people do. We decided to run some tests to see what the actual real-world limits are.
Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7:30pm ET! To join, head over to YouTube and check out the show’s live chat and our Discord!
