Armachat & Meshtastic Communicator Documentation

Latest Products

Check out our new, super-simplified messengers based on the All-in-One Heltec TRACKER architecture. These devices share the same firmware and user-friendly approach, but feature different switch configurations with full Meshtastic support.

• TrackSenger - Next-generation compact messenger
• MechSenger - Enhanced tactile interface variant

Or explore our established ESP32S3 + RFM95 LoRa platforms:

• Armachat - Our flagship communicator
• PicoKeyboard - Minimalist alternative

I am an active contributor and supporter of the Meshtastic open-source project.

Important Notice

WARNING: HIGHLY EXPERIMENTAL DEVICE UNDER ACTIVE DEVELOPMENT. NOT A PROFESSIONAL END PRODUCT.

This device offers dual firmware support for both MESHTASTIC and Armachat platforms, providing two distinct communication ecosystems on identical hardware.

Hardware Specifications

• Processor: ESP32S3 microcontroller (required for MESHTASTIC compatibility)
• Display: 2.8" IPS Color LCD with 320x240 resolution
• Input: 36-button QWERTY keyboard layout
• Key Switch: High-quality Diptronic tactile switches (100gF/1N pressure) offering a soft yet responsive mechanical-like feel
• Radio: RFM95 LoRa module for long-range communication
• Software: Armachat firmware implemented in CircuitPython - completely open-source and transparent
• Power: USB-C battery charging for standard 18650 lithium cell (battery not included)
• Dimensions: 115mm × 95mm × 18mm including internal battery compartment

> Note: Though originally designed to accommodate Raspberry Pi PICO (hence the "PICO" in the name), we now recommend the ESP32S3 implementation due to enhanced support from the Meshtastic community.

Firmware Options

Both firmware options can be installed on the same hardware, allowing future switching without hardware modifications. Some software knowledge is required, but no soldering is needed for firmware transitions.

IMPORTANT: RADIO MODULE IS NOT CERTIFIED FOR COMMERCIAL USE

ARMACHAT Features

• Implementation: Simple, readable CircuitPython code
• Compatibility: Functions on both ESP32S3 and Raspberry Pi PICO hardware
• Configuration: Edit settings directly in /lib/config.py (non-interactive setup)
• Operation: Type message and press Enter to send; system confirms delivery automatically
• Security: Optional AES256 encryption
• Usage Pattern: Single letters function as commands; longer text is treated as message content (to send a single letter message, add a space after it)
• Important Note: Communication protocol is unique to Armachat - you'll need multiple Armachat units to establish a network

Armachat Command Reference:

• [H] - Display help menu
• [E]edit - Modify selected message
• [M]emory - Count stored sent/received messages
• [L]ist - Toggle detailed message information
• [R]adio - Display radio module information
• [C]rypto - Toggle encryption on/off
• [D]ebug - Toggle debugging information
• [G]ping - Initiate continuous incrementing number transmission (for range testing)

MESHTASTIC Features

Meshtastic offers a comprehensive mesh networking platform with established community support. This implementation functions as both a standalone communicator and gateway device.

• Ecosystem Integration: Works as a gateway connected via Bluetooth to phone applications
• Input Flexibility: Send messages either through the physical keyboard or connected phone app
• Display Limitations: Screen shows only the most recently received message (no message history on device)
• Delivery Confirmation: Simple confirmation for last message (full delivery tracking available in app)
• Connectivity: WiFi and Bluetooth interfaces
• Configuration: All settings must be configured via mobile application
• Compatibility: Functions with any Meshtastic-compatible device — no need to purchase multiple units of this specific hardware
• Resources:
• Meshtastic test with phone demonstration
• Standalone operations between communicators

Purchase Options

Please Read Carefully Before Ordering

• PCB SET: White circuit boards only, no components included. Requires soldering skills and component sourcing.
• Assembled Unit: Fully functional device, available with your choice of frequency band.

Firmware Selection:

• Meshtastic: Pre-installed Meshtastic firmware
• Armachat: Pre-installed Armachat firmware

Switching Between Firmwares

1. Enter Bootloader Mode: Short the solder jumper on the BPi board and briefly press the reset button
2. For Meshtastic: Visit the web flasher tool
3. For Armachat:
4. Install CircuitPython from the official installer
5. Download and copy files from Armachat-circuitpython repository

Required Components for DIY Assembly

Main Components:

Electronic Components:

Optional Components (Bottom Battery Board):

Source Code Resources

• Raspberry Pi PICO CircuitPython Installation
• Main Code Repository and Libraries

Community and Additional Resources

Stay updated with the latest developments:

• YouTube Channel - Latest video updates and demonstrations
• Facebook Group - Community discussions and support
• Patreon - Support ongoing development with any contribution
• Twitter - Follow for announcements
• Instagram - Visual updates and build photos

Video Resources

Complete Armachat Video Collection Armachat YouTube Playlist

Performance Data

Tested Communication Range (Maximum Power, Spread Factor 12)

• 700m: Unit placed on garden desk at ground level
• 1500m: Unit positioned in window approximately 4m above ground
• 4300m: Unit installed in attic window 10m above ground (intermittent connection, not consistently reliable)

PCB Manufacturing Resources

Order PCBs directly from manufacturing services:

• MOTHERBOARD - Main circuit board
• Top Cover (Black/Gold Variant)
• Top Cover (White/Black Variant - Recommended)
• Side Panels (Left/Right - Order Double Quantity)
• Bottom Panel
• Top Panel
• Bottom Cover with Charger Cutout

Frequently Asked Questions

Why isn't ENIG gold finish available for pre-assembled units?

After several months of testing, we discovered unacceptable corrosion issues with this finish across multiple manufacturers. The finish is still available if you order boards directly from PCB fabrication services.

Why isn't black solder mask available for pre-assembled units?

This finish shows fingerprints and scratches very prominently, diminishing the aesthetic appeal over time. This finish is available if you order directly from PCB fabrication services.

Why use a separate charging module instead of integrated charging?

We prioritized repairability and flexibility. The separate module is inexpensive and can be easily replaced if damaged, extending the overall lifespan of the device.

Should I choose Armachat or Meshtastic firmware?

• Armachat: Better suited for self-contained experimentation and standalone operation. Requires multiple Armachat devices to form a network, but offers enhanced offline functionality.
• Meshtastic: More robust platform with extensive features and community support, but requires a smartphone for full functionality. No on-device message history.

With the current hardware, switching between firmware options is straightforward, allowing you to experience both platforms.

Should I use bpi-PicoW-S3 or Raspberry Pi Pico?

• For Meshtastic: Only the bpi-PicoW-S3 is supported
• For Armachat: Both boards are compatible
• For Retro computer emulation: Only the original Raspberry Pi PICO is supported