NRF-TXT - Standalone Meshtastic node for Off-Grid Texting (Complete)

Introducing the NRF-TXT
The NRF-TXT is an ultra-efficient, portable communication device designed to be the longest-running Meshtastic node possible, while remaining compact and easy to carry. This standalone unit is built for off-grid scenarios, ensuring reliable communication without requiring a smartphone or Bluetooth — though Bluetooth remains available if preferred.

Designed for outdoor adventurers, preppers, and emergency communication, the NRF-TXT integrates seamlessly with the Meshtastic LoRa platform, enabling users to establish long-range mesh networks with multiple devices to send text messages and location data. Its optimized power efficiency ensures extended battery life, making it ideal for the wilderness, disaster response, and long-term remote use.

What sets the NRF-TXT apart is its support for an optional magnetometer. Unlike GPS alone, which can tell you where other nodes are in terms of distance, the magnetometer continuously senses the Earth’s magnetic field to determine your orientation (like a digital compass). The Meshtastic firmware combines this heading data with each node’s GPS location to show live directional arrows on the screen. As you move, the arrows rotate in real time to always point toward the other nodes — so you instantly know not just how far away someone is, but exactly which direction to walk to reach them. This is especially powerful for hikers, search-and-rescue groups, or anyone coordinating in areas without cellular service.

The built-in buzzer ensures you never miss an important message, while the folding antenna improves portability, letting you carry the device without worrying about bent or damaged antennas. For those who want even more, an optional air-quality sensor provides environmental data including temperature, humidity, barometric pressure, and VOC gas levels.

Key Features:
✅ Longest-Running Portable Node – Engineered for extreme power efficiency, maximizing battery life while remaining lightweight and compact.
✅ Standalone Operation – Works independently without requiring a smartphone or Bluetooth connectivity (though Bluetooth is available if needed).
✅ Seamless Meshtastic Integration – Fully compatible with all Meshtastic nodes, allowing effortless mesh expansion.
✅ User-Friendly Interface – Features a 0.96-inch OLED display and integrated silicone keyboard for easy messaging.
✅ Buzzer Notifications – Alerts you with an audible tone whenever a new message arrives.
✅ GPS Tracking – Enables real-time location sharing, perfect for hiking, events, and emergencies. On-screen arrows point toward other nodes.
✅ Folding Antenna – Portable and durable; folds away for safe carrying.
✅ (Optional) BME680 Sensor – Monitors humidity, barometric pressure, temperature, and VOC levels.
✅ (Optional) Magnetic Compass/Gyroscope – Provides live heading and wake-on-tap functionality.

Why Upgrade from Hel-TXT (ESP32) to NRF-TXT?
ESP32 boards like the Hel-TXT are a great starting point, but they use about 10× more power — mainly because of Bluetooth. To save battery, they rely on sleep modes that can limit constant phone pairing.

The NRF-TXT provides:
- Much longer battery life with Bluetooth always available
- Optional magnetometer for real-time directional arrows
- More efficient GPS for extended runtime

In short: Hel-TXT is the starter, NRF-TXT is the upgrade.

Specifications:
- Core Microcontroller: Heltec Mesh Node T114 V2
- LoRa Chip: SX1262
- Frequency: 863–928 MHz
- Battery: 4000 mAh Li-ion (~276 h standby, ~198 h with GPS enabled)
- Antenna: Folding EOTH 868–915 MHz 2.5dBi
- Buzzer: Passive Buzzer 9042 16 Ω
- GPS Module: L76K GNSS (super-low power)
- Optional Sensor: BME680 (temp, humidity, pressure, VOCs)
- Optional Compass/Gyro: Adafruit MPU-9250
- Keyboard: 50-key silicone QWERTY
- Bluetooth: v5.0 LE
- Connectivity: USB-C port
- Dimensions: 85 × 45 × 20 mm (102 mm tall with antenna)
- Weight: ~8 oz

Package Contents:
📦 NRF-TXT Device
📦 Built-in Rechargeable Battery
📦 Folding Antenna
📦 User Guide

Disclaimer:
I am responsible for the assembly, case design, and device configuration. However, I do not provide support for the Meshtastic app itself.

Due to the 3D-printed nature of the case, there may be small surface imperfections outside my control, but I am fully committed to delivering the highest possible quality within my ability.