LORA and Meshtastic for Off-Grid Mesh Networks

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-LoRa is a proprietary radio communication technique based on spectrum modulation. It enables long range, low power radio messaging at the cost of low bandwidth. 

-LoRaWAN is a method of using the LoRa platform for wide area mesh networks where every node on the network is both a transmitter and receiver. This enables messages to reach any node on the network, regardless of distance. 

-Meshtastic is an open source software, designed to run on LoRaWAN units to standardize communication across the network. It enables message encryption, direct messaging, designated message channels between units, and many other features. 

-The hand held units are comprised of an ESP32 based LoRa unit by HelTec Automation called the HelTec V3. This is a standard entry level LoRa board. The design has been augmented by a pair of 5V solar cells wired in parallel to a 5V MPPT charge controller, and a 3000Mah lithium ion battery.

-The radio is connected to any smartphone via a bluetooth connection to the Meshtastic app, which enables messaging and configuration of the radio software. 

-This culminates in an off grid radio that can be charged with solar power, and functions in the absence of active wifi and cellular networks. 

-The custom RPi unit is comprised of a Raspberry Pi 4B outputting to a 7in touchscreen display. Hooked to the Pi is a WaveShare sx1262 LoRa hat which functions as the LoRa component as well as enabling GPS functionality. Power is sourced from a 10,000mAh lithium ion battery and distributed through a power distribution board that allows USB-C charging of the unit. 

-The Meshtastic software currently runs through a local host webserver, however, I am currently working on adding a locally running user interface to interface with the node directly. 

-Goals for the unit include eliminating the wireless insecurity of Bluetooth and wifi, integration of modular sensor packages such as environmental sensors, dosimeters and GPIO capability, and IP 64 waterproofing. 

-The goals for this project are as follows:

-Create a Meshtastic node that can function off grid for an indefinite amount of time using only solar power for sustainment. This is useful for disaster preparedness and for situations like large gatherings, where cellular networks can be unreliable. 

-Eliminate the insecurity of the bluetooth link to a smartphone by utilizing a direct wired connection from the LoRa node to an input device. 

-Create a framework for modular sensor packages and larger computing capacity while maintaining rugged waterproof design.