# EFHW-Switch — Bluetooth Relay Board + Flutter App

Year: 2024  
Type: Personal  
Category: embedded  
Page: https://eliachiarucci.com/projects/efhw-switch

Battery-powered BLE relay for ham radio antenna switching. CR2032 powered with 12-month battery life, running Zephyr RTOS on nRF52832.

## Overview

EFHW-Switch is a Bluetooth-enabled remote relay designed for ham radio antenna switching. Built on the Nordic **nRF52832** running Zephyr RTOS via the nRF Connect SDK, the device is powered by a single CR2032 coin cell with a target battery life of up to 12 months.

The ultra-low-power design uses a latching relay to minimize energy consumption, the relay only draws current during switching, not while holding state. A companion Flutter app provides BLE control from any mobile device.

The custom PCB follows Nordic development patterns and can be flashed via a Nordic devboard with Segger RTT or alternatively through an FTDI board with OpenOCD.

## Key Features

- Ultra-low-power design — up to 12 months on CR2032
- Latching relay for minimal power draw
- Bluetooth Low Energy control
- Zephyr RTOS on Nordic nRF52832
- Custom PCB design
- Flutter companion app for mobile control

## Tech Stack

C, Zephyr RTOS, nRF Connect SDK, Nordic nRF52832, Flutter, Dart

## Links

- Website: https://www.morsekey.net/efhw-switch
- GitHub: https://github.com/eliachiarucci/EFHW-Switch