Build an Armachat LoRa Communicator (Make: Magazine)

Overview

Published by Make: Magazine, this step-by-step tutorial guides you through building the Armachat — a battery-powered, text-based LoRa walkie-talkie with an extremely low component count (around 25 parts). The project covers soldering, firmware flashing, and operating the device for long-range off-grid communication.

What You'll Build

A handheld LoRa communicator featuring:

• RFM95 LoRa radio module for long-range wireless communication
• QWERTY keyboard with 30 tactile buttons
• TFT LCD display
• SMA antenna connector
• Optional LED backlighting (one LED per key)
• 18650 battery power

Build Steps

1. Solder the RFM95 LoRa radio module — the first and most critical step
2. Flash the Arduino firmware and verify "LoRa init succeeded" on the display
3. Solder the buttons — 30 tactile switches for the keyboard
4. Attach the SMA antenna connector
5. Optional: Solder 30 backlit LEDs for keyboard illumination

Operation

The communicator is controlled via keyboard shortcuts:

• Press S from the main screen for Setup (frequency, LoRa settings, ID)
• Address book supports 10 contacts with fixed names
• Configurable spread factor and radio transmission power
• Messages are automatically resent when recipients come in range

Skills Required

Basic through-hole soldering. The design uses minimal active components and is deliberately accessible to makers of all skill levels.