Nodemcu NTP clock with Max7219 LED matrix

Hardware parts

• Nodemcu v3 board
• MAX7219 Dot Matrix Module For Microcontroller 4 In One Display with 5P Line

Pinout

Pinout:

• Connect 3V to VCC
• Connect G to GND
• Connect D5 to DIN
• Connect D6 to CS
• Connect D7 to CLK

Note: it's all sequential

Software dependencies

This uses the Arduino IDE with the esp8266 core and the following libraries, installed using the Libraries manager:

• ezTime 0.8.3, to get time from NTP pool, properly format it and take in account timezones
• MajicDesigns's MD_MAX72XX library 3.2.1, to write hours on the Max7219 LED matrix (this builds mostly upon the MD_MAX72xx_PrintText sample)