EFHW-Switch

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