Project

Keypad Controller PCB

Advanced 20-button matrix scanning with ESP32 and integrated power management.

September 2025
PCB Design ESP32 USB-C Integration Battery Management

The Keypad Controller PCB is a robust circuit board designed for precision 4x5 button matrix scanning via the ESP32 DevKit platform. It features an integrated LiPo charging circuit with USB-C connectivity, making it an ideal core for wireless industrial interfaces or high-end DIY controllers.

The design prioritizes stability and protection, including a TP4056 charging IC, TVS overvoltage diodes, and a PTC resettable fuse. A boost converter ensures a rock-steady 3.3V supply across the entire battery discharge cycle. The 20 Omron tactile switches are arranged for optimal feedback and durability.

With its shape-optimized layout and professional component selection, this PCB is a ready-to-deploy solution for wireless IoT keypads and custom embedded HMI systems.

Who is this for?

This keypad controller is a good fit for anyone who needs a wireless, battery-powered control panel, for example for industrial machinery, a custom home-automation panel, or a DIY project with physical buttons. It's also a useful reference for companies looking for a ready-made, well thought-out design to build on, rather than developing a rechargeable button-matrix board from scratch themselves. Anyone curious how a simple keypad is turned into something wireless and rechargeable will find a concrete example here.

What makes it special?

What makes this design special is the combination of a large number of buttons, wireless operation, and carefully thought-out power management on one compact board. Twenty buttons are read reliably without needing a tangle of wiring, while the built-in battery charging over USB-C works just as simply as charging a phone. Because the power supply stays stable across the entire battery discharge cycle, the panel remains just as reliable at the end of a working day as at the start, making it easy to use as the basis for your own product.

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