This matrix display board is designed to run a 24x8 LED matrix for a personal clock project. I am using the MD_Parola library with HARDWARE_TYPE MD_MAX72XX::FC16_HW to run the display over an SPI bus.

Key components:

• 3X Miniature Ultra-Bright 8x8 White LED Matrix from Adafruit

• 3X MAX7219CWG+ IC DRVR 7 SEGMNT 8 DIGIT 24SOIC

• 3X RES 10K OHM 1% 1/4W 1206

• 3X CAP CER 0.1UF 50V X7R 1206

• 1X CONN HEADER R/A 5POS 3MM

Unfortunately the 7-segment drivers and LED matrices aren’t cheap so stuffed boards run over $50 each. Would be cool to see a lower-cost version of this concept shared.

With some minor customizations using matrix.addChar() to the ; and 1 characters, I can fit all 12-hour times on the 24x8 matrix. My code uses charOneThin for the leading one and alternates between charSemicolon and charSpace for the flashing hour-minutes separator.

uint8_t charSemicolon[] = {1,36};
uint8_t charSpace[]     = {1,0};
uint8_t charOneThin[]   = {4,130,255,128,0};
uint8_t charOne[]       = {5,0,130,255,128,0};
uint8_t charTwo[]       = {5,198,161,145,137,134};
uint8_t charThree[]     = {5,66,129,137,137,118};
uint8_t charFour[]      = {5,15,8,8,255,8};
uint8_t charFive[]      = {5,79,137,137,137,113};
uint8_t charSix[]       = {5,126,137,137,137,114};
uint8_t charSeven[]     = {5,3,1,225,17,15};
uint8_t charEight[]     = {5,118,137,137,137,118};
uint8_t charNine[]      = {5,70,137,137,137,126};