Rechargeable Power Conversion for a Children's Casio Keyboard

I took a children's Casio keyboard that depended on a fragile micro-USB input and disposable batteries. The goal was to convert it into a reliable rechargeable device without changing the outside form.

I reverse-engineered the internal layout and integrated a lithium battery with a charging module. Because the internal space was tight, I designed a custom battery holder and charging-board bracket in Fusion 360, then 3D-printed both parts.

The keyboard now charges cleanly and is much more practical for everyday use. This project combines hardware teardown, embedded integration, and compact mechanical design.