Multihop LoRa with TTGO-T-Beam

This project tries to implement multihopping data relay on the network of ESP32 modules -- TTGO-T-Beam nodes. It uses flood routing from the project: Flood Routing with Motelib.

Quick Start

Hardware Assembly

Connect T-Beam with UART-RS232

The firmware uses UART2 for communicating with the weather station through UART-232 module, while UART0 and UART1 are used for debugging and connecting with GPS respectively. The signal pins between the two modules are connected as following:

• [T-Beam].2 (TXD2) <--> [UART-232].TXD
• [T-Beam].13 (RXD2) <--> [UART-232].RXD
• [T-Beam].GND <--> [UART-232].GND
• [T-Beam].5V <--> [UART-232].VCC

Connect T-Beam with Weather Station through UART-RS232

Board of the weather station sends data through DB9 connector. T-Beam receives the data with the transceiver board, UART-232 module. The DB9 pins are connected as following:

• [station].2 (TX232) <--> [UART-232].3 (RX232)
• [station].3 (RX232) <--> [UART-232].2 (TX232)
• [station].5 (GND) <--> [UART-232].5 (GND)

Firmware

• Use Vscode plus Arduino extension to open the project in directory src.
• Compile and flash into a T-Beam board without any re-configuration. The code will automatically dectect revision of the board.
• At runtime, pass a command to set id as 0 for the node connected to the gateway device.
• The work flow is explained in the next section.

System Overview

How Firmware Work

1. After booting, a T-Beam node will be waiting data passed from its attached weather station.
2. If the data is available through UART2, the node sends it out via the routing protocol to the sink node id 0 which is determined to be connected to the gateway.
3. The sink node sends out the data it received, to the gateway through UART0 -- debugging port.

Routing

• Project that is provided the routing mechanism.

Terminal Commands

On purpose, these commands could be send to T-Beam through UART0, debugging port.

• help for listing all commands.
• hello for testing only.
• node_id for setting node id, e.g.,
  • node_id for asking the current node id.
  • node_id <id> for setting the new id where in [0..25535].
• vtube <params> for forwarding data through UART2.

TTGO-T-Beam

Pinout

Rev.0.7

Rev.1.0

Rev.1.1

Resources

Hardware References

• All versions' schematics

• V0.7 information

• LiLy TTGO T-Beam 0.7

• LiLy TTGO T-Beam 1.1

• SoftRF

Examples

• Examples for each peripheral on T-Beam

• Low-power design guide for T-Beam

• Most comprehensive resource on Riot-OS website

• SPI Bug Fix on Sendeepmistry's LoRa Library -- reconfirmed with Arduino SPI Library