Project Hydra (Meshtastic PCB)

A minimalist PCB design built around the Ebyte E22-900M30S 30dbm (1 watt) LoRA radio and the ESP32-WROOM-32U cpu compatible with the Meshtastic-device firmware.

Features

• Supports up to 30dbm (1 watt) transmit power (Please check local ISM band regulations for power limitations)
• OLED support via I2C
• GPS support via UART
• PSRAM support
• User button via pin header
• Switchable 3.3V power rail (GPS power saving)
• ADC input for battery voltage sensing
• Single 5V input (no reverse polarity and overvoltage protection!)
• 3.3V output (or input if onboard buck converter is not assembled)
• Two GPIO reserved for future use (for example power control)
• Programmable via USB-Serial adapter (RTS/DTR are required for the on-board auto reset!)
• Compatible with "meshtastic-diy-v1" target in Meshtastic-device firmware

Project status

• V2.1 has been published and introduces breaking changes.
• Production file generation has not been verified yet for all variants.
• Core PCB KiCad footprint and schematic symbol will be available afer the official V2 release.

Ordering from JLCPCB

• Basic ordering instructions can be found at the ordering page.

Assembly instructions

• Use the fancy iBom for reference!
• Start with the 3.3v step down regulator and test the 3.3v rail first.
• Assemble all the parts for the auto reset circuit and the ESP32 module. Don't forget to connect the 2.4G antenna!
• Try to program the core pcb next.
• Lastly, populate the RF modem. You can use a strip of cardboard as a spacer to leave a small gap between the two PCBs, in case the ESP32 stops working you can use solder wick to easily remove and reuse the RF modem.
• Never ever turn on the core pcb withount an antenna! This may infuriate the RF gods and you inevitably end up performing a sacrifial ritual to please the RF gods with magic smoke.
• PSRAM is optional

Contributing

Please contribute using Github Flow. Create a branch, add commits, and open a pull request.

Support

Please open an issue for support.

License

GPL v3

Meshtastic® is a registered trademark of Meshtastic LLC. Meshtastic software components are released under various licenses, see github for details. No warranty is provided - use at your own risk.