PCB Led dispaly wifi clock

The PCB LED display wifi clock operates by combining wireless connectivity, sensor data acquisition, and complex matrix multiplexing on a custom FR4 printed circuit board. At the core of the system is an ESP32-C3 microcontroller, which features built-in Wi-Fi capabilities. Upon powering up and connecting to a local wireless network, the ESP32-C3 queries an online Network Time Protocol (NTP) server to automatically synchronize the current time, eliminating the need for manual clock setting or an external battery-backed real-time clock module. Concurrently, onboard temperature sensor components measure the ambient thermal conditions, providing local data that the microcontroller processes alongside the time variables. To drive the visual elements on the transparent FR4 PCB, the design utilizes charlieplexing—a technique that drives a large number of LEDs using a minimal number of microcontroller I/O pins by exploiting the tri-state logic of the GPIOs to selectively forward and reverse bias individual diodes in rapid succession. Persistence of vision ensures the human eye perceives a stable, continuous display of both digits and sensor metrics. Developers can program and debug the system using either the Arduino IDE or the lower-level ESP-IDF framework in C/C++, allowing for deep control over network protocols, display refresh rates, and power-saving modes.