Electronicsin progressMay 2, 2026· updated June 10, 2026
LED Matrix Word Clock
A WiFi-synced word clock driven by an ESP32 and a 16x16 addressable LED matrix.
#esp32#leds#pcb#3d-printing
I’ve wanted a word clock for years. This one tells the time in words on a 16×16
grid of addressable LEDs, syncs over WiFi via NTP, and dims itself at night.
The plan
Brain: ESP32 (WiFi + plenty of GPIO)
Display: 256 WS2812B LEDs behind a laser-cut letter stencil
Power: 5V/4A supply — those LEDs are hungry at full white
Enclosure: 3D-printed frame, oak face
Build log
Driving the matrix
First milestone was getting the panel lit and addressable. The trick with a
serpentine layout is mapping (x, y) to the LED index:
uint16_t xyToIndex(uint8_t x, uint8_t y) { return (y % 2 == 0) ? y * 16 + x : y * 16 + (15 - x);}
Time sync
NTP over WiFi was painless. Next up: a light sensor for auto-dimming and a
custom PCB so I can ditch the breadboard.
