DIY No PCB
A minimal hand-wired build using off-the-shelf parts. No custom PCB needed — just an Arduino-compatible board, a buzzer, and a jack.
$15–30
Open source — source your own parts
This is the simplest way to get a Vail adapter running. Wire up a few components on a breadboard or perfboard, flash the firmware from GitHub, and you've got a working CW interface. It's a good option if you enjoy building things from scratch or want to learn how the adapter works.
You can add optional features like capacitive touch keying, audio output, or even radio keying — but those require extra components (transistors, resistors, etc.).