Now available directly from OSH Park: https://oshpark.com/shared_projects/xeBcFP0G

This is a shield/breakout for the Wemos D1 Mini (and D1 Mini Pro) ESP8266 board that makes it easy to control addressable RGB LEDs, such as WS2811, WS2812 (Adafruit NeoPixels), and APA102 (Adafruit DotStars). The Wemos D1 Mini is an excellent mini Wi-Fi development board, based on the ESP8266. I've used it extensively in development of addressable RGB LED art projects, such as my 6.5ft Rainbow Tree, Bloom v2, and Ducenti. This shield supports 6x parallel output.

I made this shield because I was hand-wiring this same layout on perma-proto boards, which was time-consuming and unprofessional looking.

The shield includes a 74HCT245 level shifter, which is the most well-regarded high speed level shifter I've found. This shifts the 3.3V logic level of the ESP8266 to the 5V expected by addressable RGB LEDs. These projects often work fine without a level shifter, until they don't.

Six digital output pins (D1, D2, D5, D6, D7, D8) are run through the level shifter. These pins support parallel output by the fantastic FastLED library.

The shield also includes data line resistors and a large 1000uF capacitor, as recommended when driving LEDs, especially when powering the microcontroller from the same power supply as a large number of LEDs.

The 90 mil, double-sided 5V and GND traces should be rated for up to ~12 amps. That's enough for about 200 LEDs at max output (solid white, full brightness), and much more than 200 LEDs at lower output, lower brightness, and/or multicolor patterns. A barrel connector can be added to connect a power supply, but most are only rated for 2.5A (~50 LEDs at max output). For larger quantities, power should be connected to the PCB directly with large gauge wire, connected directly to the LEDs, and/or brightness should be limited in software. It is very important when using high current power supplies and large numbers of LEDs to watch for overheating on wiring, connectors, components, and the PCB.

Specifications

• Size: 1.64 x 1.71 x .063 inch (41.61 x 43.4 x 1.6 mm)
• 2 layer printed circuit board
• FR4 substrate
• Lead free
• Purple SMOBC (solder mask over bare copper)
• ENIG (Electroless Nickel Immersion Gold) finish
• Manufactured in the USA
• Current Rating: 12A

Parts List

These parts are required to assemble. They are not included.

• Wemos D1 Mini

These parts are also required to assemble. They are included if you choose the Component Kit option:

• SN74HCT245N Level Shifter
• 1000µF Capacitor
• 0.10µF Capacitor
• 330 Ohm resistors
• Power Barrel Connector Jack

Full assembly instructions