Meshtastic! An Encrypted, Off-Grid Networking Device
For years, the holy grail of portable communication devices has been mesh networking. Instead of using high power transmitters and long antennas like amateur radio, or base stations like the common cell phone, mesh networking promises a huge coverage area with small, cheap transmitters. The only caveat is that there are enough devices to actually create a mesh network.
Currently, LoRA technology is the best way to get to where we want, and the Meshtastic from B&Q Consulting Shop in Shenzhen is an excellent solution to creating a useful mesh network! Inside the Meshtastic is a Semtech SX1276 LoRA transceiver, alongside an ESP32 WROOM module and a GPS module. By connecting the credit card-sized Meshtastic module to your smartphone, you can send data over an improvised mesh network over LoRA. Think of the Meshtastic as a LoRA modem for mesh networks, using your phone and an app as the actual interface.
More information about Meshtastic can be found with the documentation, alongside the hackaday.io project page, and firmware and schematics. There is a really incredible writeup on the use and capabilities of the Meshtastic on their blog, showing how even in urban environments a low-bandwidth network can be made without any other infrastructure.