[Submission] MeshTalk T9 Communicator

[iamakshaymore]

Your Name

Akshay More

Email

akshaypm94@gmail.com

GitHub Repository Link

https://github.com/iamakshaymore/meshtalk_t9_communicator

Project Description

MeshTalk T9 Communicator

Overview

This is a custom fork of the stock Meshtastic firmware developed for the Seeed Studio Meshtastic Build-Off 2026. The project aims to create a standalone LoRa communicator that can be used like a phone, without needing a Bluetooth connection to a mobile app.

Currently, the fork implements a custom keyboard-driven UI with T9 input, network visualization, and message management. The built-in screens on the development boards have been bypassed in favor of a custom SPI TFT display (ST7789 240x320) and a physical 4x4 matrix keypad. This setup is currently working on the Heltec V3 (heltec-v3-custom) and Heltec V4 (heltec-v4-custom) variants.

Current Features

• Custom T9 text input for on-device messaging
• LoRa network node visualization and signal strength indicators
• Message management (send, receive, and history)
• Direct messaging and channel messaging support
• Favorites management
• Battery monitoring and power management
• Bluetooth disabled by default to reduce power consumption

Custom Hardware (ESP32-S3 + Wio-SX1262)

While the Heltec boards provided a good baseline for developing the UI, the goal for the Build-Off is to design a dedicated board. To meet the competition's focus on the Seeed Studio ecosystem, we are transitioning to custom hardware.

The custom board uses the Wio-SX1262 wireless module for LoRa communication and an ESP32-S3 microcontroller. This combination provides the necessary GPIO pins to drive the SPI TFT display and the 4x4 matrix keypad without running into the pin constraints of off-the-shelf boards.

Phase 1: PCB Design

• Design the schematic and PCB around the ESP32-S3.
• Integrate the Wio-SX1262 module.
• Include headers/connections for the matrix keypad and SPI display.
• Implement power management and battery charging circuitry.

Phase 2: Firmware Adaptation

• Port the custom UI module to the new board definition.
• Map the new GPIO pin configurations.
• Create a dedicated PlatformIO variant for the custom board.
• Optimize power management for the new hardware.

Phase 3: Testing and Validation

• Validate basic functionality against the Heltec V3/V4 baselines.
• Conduct range and mesh network performance testing.
• Profile power consumption.
• Prepare documentation for the Build-Off submission.

Tech Stack

Hardware Stack

• Microcontroller: ESP32-S3 (Chosen for its robust processing power and ample GPIO availability)
• LoRa Radio: Seeed Studio Wio-SX1262 Wireless Module (Ultra-low power, long-range RF)
• Display: 2.4" or 2.8" SPI TFT Display (ST7789 driver, 240x320 resolution)
• Input: Custom tactile 4x4 Matrix Keypad
• Power: Integrated battery management/charging circuitry for a standard 3.7V LiPo

Software / Firmware Stack

• Core Firmware: Custom fork of the official Meshtastic Firmware
• Language: C++17
• Build Environment & Toolchain: PlatformIO
• Key Software Implementations:
  • Custom hardware-specific variant definitions for PlatformIO
  • Custom T9 text input algorithm mapping
  • Direct SPI display driving and UI rendering bypassing the stock screen modules

Message to the Organizers

Hi Seeed Studio Team!

I'm incredibly excited to submit the MeshTalk T9 Communicator for the 2026 Build-Off. My goal is to build the ultimate standalone Meshtastic communicator, completely bypassing the need for a Bluetooth-paired smartphone.

I currently have the custom firmware, UI, and T9 input system fully working on prototype development boards. However, to realize the final vision, I am designing a custom PCB utilizing the Wio-SX1262 module paired with an ESP32-S3 to ensure I have enough GPIOs to drive my external SPI display and physical matrix keypad.

As I finalize the PCB design in Phase 1, I am very interested in leveraging Seeed's PCBA services for manufacturing the prototypes. I would love to know if my project qualifies for the PCBA prototyping sponsorship/discount associated with the Build-Off.

Thank you for hosting this, and I look forward to sharing my hardware progress soon!

[iamakshaymore]

Hi @Seeed-Team, the hardware layout for the communicator is officially complete!

Before I proceed with Fusion PCBA service, I would massively appreciate it if an engineer could give my schematics and wiring a quick sanity check.

To be totally honest, this is my first time designing a board around a raw ESP32-S3 from scratch. I've a custom battery unit and charging circuit, USB-C, the Wio-SX1262 LoRa module, an SPI display, and a 4x4 matrix keypad.

Since it's my first time tying all these specific subsystems together, I just want to make sure I’m not missing anything obvious (like a missing pull-up resistor, a wrong capacitor value, or a USB-C routing mistake) before I pay for assembly.

The raw KiCad files and exports are pushed to the repo here: [https://github.com/iamakshaymore/meshtalk_t9_communicator/tree/hacker-central-ui/meshtastic-build-off-2026/Hardware]

Let me know if you spot any red flags or if it looks good to go!

[iamakshaymore]

Update :

Hardware: PCB design is finalized and sent to SenseCap for manufacturing.

Firmware: Currently polishing the firmware. The code is already fully functional on Heltec V3 and V4 development boards with the custom 4x4 keyboard and 2-inch SPI display attached.