DIY electronics enthusiasts are finding creative ways to shrink powerful microcontrollers into portable, daily-carry gadgets, and custom electronic keychains have quickly become a favourite project. Designed around the ultra-compact Seeed Studio XIAO ESP32-S3 board, this minimalist build by Tech Talkies combines an interactive 1.3-inch OLED display, a tiny LiPo battery, and a power slide switch into a remarkably thin 3D-printed enclosure. By leveraging the microcontroller's integrated battery management system, the setup stays lightweight while delivering rechargeable functionality in a pocket-sized form factor.
The assembly process emphasizes efficiency and precise spatial planning. Standard wiring routes the battery directly to the back charging pads of the board, with a slide switch placed in series along the positive line while the OLED display hooks up using just four leads for power (3.3V, Ground) and I2C communication (D4 for SCL, D5 for SDA). Secured cleanly inside the enclosure using M2 hardware, the build takes advantage of the microcontroller's onboard status LEDs to show active battery charging directly through the housing.
Programmable via the Arduino IDE, the project offers a fully customizable platform for displaying animations, simple games, or sensor readouts on the go. Its combination of accessible open-source code and simple components makes it an ideal beginner-to-intermediate build for anyone looking to practice custom CAD design, 3D printing, and compact electronics assembly.
