LED Keychain

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LED-Keychain

A small programmable LED keychain designed in KiCad and powered by an ATtiny412.

This is my first PCB project, so the main goal wasn't to create something revolutionary. I wanted to learn the complete hardware design process: creating a schematic, assigning footprints, routing a PCB, generating Gerber files, and writing firmware for a microcontroller.

Features

• ⭐ Star-shaped PCB
• 🌈 8 addressable SK6812MINI-E RGB LEDs
• 🔋 Powered by a CR2032 coin cell battery
• 🔘 Push button for switching lighting modes
• ⏻ Power switch
• 💡 ATtiny412 microcontroller

How it works

The ATtiny412 controls all eight addressable LEDs. Since they are individually addressable, different lighting effects can be created in software.

The button is used to switch between animation modes, while the power switch completely turns the keychain off to save battery.

Components

• ATtiny412-SS
• 8 × SK6812MINI-E RGB LEDs
• CR2032 battery holder
• Push button
• Slide switch
• 330 Ω resistor
• 100 nF capacitor
• 100 µF capacitor

Project files

• KiCad schematic
• PCB layout
• Gerber files
• Bill of Materials (BOM)
• Arduino firmware

What I learned

Before this project I had almost no experience with PCB design.

During development I learned how to:

• create a schematic in KiCad;
• assign footprints;
• route PCB traces;
• use copper pours;
• generate Gerber files;
• prepare a project for manufacturing.

There were a lot of mistakes along the way, but fixing them taught me much more than if everything had worked on the first try.

Thanks for checking out my project! :)