Now available directly from OSH Park: https://oshpark.com/shared_projects/6tHcl6u3

This is a shield/breakout for the Wemos D1 Mini 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

This is a smaller version of my Wemos D1 Mini ESP8266 LED & Level Shifter Shield

I made this shield on request for a smaller shield, compatible with other Wemos D1 Mini stacking shields.

The shield includes the slightly smaller 74HCT125 level shifter. It belongs to the same family as the 74HCT245, 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.

Four digital output pins (D5 - D8) are run through the level shifter. These pins support parallel output by the fantastic FastLED library.

The shield also includes places for data line resistors as recommended when driving LEDs. Duplicate breakouts are included for each of the Wemos D1 mini pins. This shield omits the large 1000uF capacitor included on the larger shield, due to limited space. The large capacitor can be connected across the power and ground connections at the strip.

Assembly Options

The board can be assembled in a very low profile configuration (about 10mm thick) by soldering the Wemos directly to the PCB with only male headers (see pictures).

Alternatively, female headers can be used to allow easy removal of the Wemos microcontroller. This results in about 18mm of thickness.

Stacking female headers can be used, which allows plugging other Wemos shields directly on top and/or bottom. This adds another 8mm to 16mm of thickness.

3D printed enclosure files are available on Thingiverse.

Specifications

• Size: 1.02 x 1.10 x .063 inch (25.83 x 27.89 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

Parts List

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

• Wemos D1 Mini & Headers

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

• SN74HCT125N Level Shifter
• 0.10µF Capacitor
• 4 x 330 Ohm resistor

Full assembly instructions