This instructables show how to use ESP8266 and 25 LEDs to create an IoT LED Sign.

Step 1: Preparation

LED

SK6812 SMD5050 x 25

ESP8266

WeMos D1 Mini Pro

Connect Wire

0.5 mm uncoated wire

Case

3D print: http://www.thingiverse.com/thing:2135569

Other

3 short coated wire to connect between ESP8266 and LED
some tape for insulation
M1 screw x 4

Step 2: LED Matrix Assembly

This LED matrix design used zigzag pattern and rotated all SMD 30 degree to reduce soldering point. Each pixel only 6.4 mm apart, it is highest density SMD5050 LED matrix I ever seen. Please read the data sheet carefully before plug the SMD in the 3D model, the first LED out point touch second LED in point. Each row have different direction, row 1, 3 and 5 have same direction, row 2 and 4 rotated 180 degree.

After place the LEDs, follow the 3D model pit cut the wire and push it in.

Ref.: https://cdn-shop.adafruit.com/product-files/1138/S...

Step 3: ESP8266 Board Assembly

Plug the WeMos D1 Mini Pro board to the 3D model, done!

Step 4: Soldering Work

Soldering all touch point, each LED soldering 3 - 4 points. Some LED may fail in high temperature, so I suggest test after finished soldering each LED. After soldering all 25 LEDs and tested ok, soldering to the ESP8266 board:

ESP 5V -> LED +ve

ESP GND -> LED -ve

ESP D4 -> LED in

Step 5: Screw Up

Screw up with the M1 screw.

Step 6: Flash NodeMCU WebIDE

Flash the latest version of NodeMCU WebIDE, you may see my previous Instructables for more details.

Edit config.lua and connect your mobile to the same WiFi, then browse to http://nodemcu-webide.local/led-sign.html and design your first LED sign.

Step 7: Happy Programming!

led-sign.html and led-sign.lua are only a very simple example show what you can done in NodeMCU WebIDE. You may browser other sample and edit your own code over WiFi with your mobile!