Keypad Controller PCB
A compact 4x5 button matrix controller with ESP32 DevKit and LiPo power via USB-C. Robust solution for wireless keypad control with integrated charging circuit and protection.
September 2025
Project Description
The Keypad Controller PCB is a versatile circuit board that reads a 4x5 button matrix via an ESP32 DevKit. The board is powered by a LiPo battery pack that can be recharged via a USB-C connector, enabling wireless operation without external power.
The design includes an integrated charging circuit based on the TP4056 chip with LED indication for charging status. The circuit board features extensive protection: a PTC resettable fuse on the USB port, TVS diode for overvoltage protection, and a boost converter that provides stable 3.3V power supply for the ESP32.
The button matrix consists of 20 Omron B3F tactile switches in a 4×5 configuration. Reading is done efficiently via matrix scanning: columns are driven low one by one, while rows are read via internal pull-ups of the ESP32.
The circuit board is shape-optimized and includes mounting holes for easy mounting in enclosures. The USB-C connector is centered at the bottom of the PCB for ease of use. This makes it a robust solution for wireless controllers, IoT projects, and embedded keypad applications.