APRS and Meshtastic are the two most important mesh networking technologies today. For a few years now people have been deploying solar-powered meshtastic repeaters. The current draw on RAK-based mesthastic devices is extremely low and lends itself well to solar powered installations. Until recently, however, ham radio APRS digipeaters were difficult and expensive to run on solar power. This all changed with the introduction of the LILYGO T-TWR Plus, a 2 meter ham radio built on top of an ESP32 computer. The T-TWR Plus can be flashed with custom firmware to become a small 2-watt APRS digipeater with low power draw – perfect for solar power.
The total project cost is less than $300. For around $1000 a group could deploy four of these around a city, providing off-grid communications for thousands of people for less than the cost of a single HF ham radio.
The combination of Meshtastic and APRS allows anyone with or without a ham radio license to communicate via wireless mesh network.
In the future someone might also be able to connect these devices together in order to pass traffic between the APRS mesh network and the Meshtastic mesh network.
Components:
| Item | Product Name | Cost | Link |
|---|---|---|---|
| Solar Panel | Soshine 12W | $30 | Amazon or AliExpress |
| Battery | Voltaic Systems V25 | $44 | Amazon or Volatic Systems |
| Meshtastic Rak Board | RAK Meshtastic Kit | $37 | Rokland |
| APRS Board | LILYGO T-TWR Plus VHF | $50 | (purchase links at bottom of this page) Note: T-TWR Plus VHF Only. Do NOT select “OpenEdition” |
| Meshtastic Antenna Connector | IPEX to N Type Female | $4 | Amazon |
| Meshtastic Antenna | 915 MHz 3 dBi N-Female | $39 | Rokland |
| APRS Antenna Connector | SMA male to UHF SO-239 Female | $7 | Amazon |
| APRS Antenna | Bingfu Mobile Antenna | $37 | Amazon |
| Box | ABS Box with mounting tabs, 158mm x 90mm x 46mm | $9 | Amazon or AliExpress |
| Drain Plug | VENT-PS1YBK-N8001 | $5 | Mouser or Amazon |
| USB Cable Pass-Through | 3/4 NPT Cable Gland | $2 | Amazon |
| Antenna Wrap | Proxicast | $2 | Amazon |
| Coax Cable For Meshtastic | 2′ KMR400 N to N | $13 | Amazon |
| $279 |
Flashing the Meshtastic Repeater:
Make sure the antenna is connected before you power on the device. Try not to touch the metal components on the board with your fingers while the device is powered up.
Using a Chrome browser follow the instructions here: flasher.meshtastic.org
Configure the device using this: https://client.meshtastic.org/
Be sure to set the device role to “Router” and set the location to “fixed” while you are on-site installing the node – this will allow it to show up on the map for everyone on Meshtastic.
Flashing the APRS Repeater:
Make sure the antenna is connected before you power on the device. Try not to touch the metal components on the board with your fingers while the device is powered up.
Follow the instructions to flash the device from here: https://github.com/nakhonthai/ESP32APRS_T-TWR
In the hardware menu of the device be sure to set the OLED display to “DIM.” There is a known issue where the display cannot be turned completely off, this results in increased battery drain and hopefully in future firmware releases this issue will be addressed.
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