Michigan’s Own Low-Power, Low-Form-Factor LoRa Node for Meshtastic

Simple NRF52840 / E22 Meshtastic node in an ultra-small form factor.

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🛠️ Installation Method

1. Solder the E22 Module
   Use hot air or a hotplate to solder the E22 to the backside of the board.

2. Install Pin Headers
   Solder pin headers on the front side of the board, bottoming them out on the E22.

3. Battery Connection (Optional)
   If you want a directly connected battery, solder the two jumpers on the bottom of the MCU.

4. Battery Voltage Reporting (Optional)

   • R1 and R2 can remain unpopulated if you don’t need battery voltage monitoring.

5. Fuse Configuration (Optional)

   • F1 and F2 can be jumpered.
   • These are resettable fuses for those of us who can’t always follow P+ and P- directions (like me).

6. Add I2C Screen (Optional)

   • Solder a I2C SSD1306 Screen to the pin pads.
   • I reccomend Dual Colored Oled

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💾 Flashing Meshtastic Firmware

1. Put the Board in Bootloader Mode

   • Connect the USB cable to your computer and Pro-micro
   • With a small metal object, short the GND and RST pin on the Pro-micro quickly twice
   • The board should appear as a USB drive

2. NEW BOARDS ONLY: Update the NICE_NANO Pro-micro Bootloader

   • If this is your first use of a new Pro-Micro, a bootloader upgrade is required
   • Download and unzip the Pro-micro_bootloader_update.zip file.
   • DO NOT COPY BOTH FILES AT THE SAME TIME
   • Copy the Hex file FIRST and drop it onto the USB drive
   • Then copy the UF2 file NEXT and drop it onto the USB drive
   • The drive will disconnect
   • Unplug the device and keep it powered off for 10 seconds.
   • Plug it back in and start over with #3
   • YOU WILL NOT BE DOING THIS AGAIN.

3. Flash via Meshtastic Flasher (Recommended)

   • Download firmware from Meshtastic Flasher.
   • Select "NRF52 Pro-micro DIY"
   • Select your firmware version.
   • Click Download and wait for completion.
   • Drag the downloaded firmware file to the Pro-micro USB drive.
   • The drive will disconnect
   • Unplug the device and keep it powered off for 10 seconds.

   OR

Flash via Command Line

4. Install Dependencies
   Make sure you have Python and the esptool or nrfutil utilities installed.

   For NRF52840 boards, you can also use the Meshtastic Flasher GUI or dfu-util.

5. Download Firmware

   • Get the latest NRF52 firmware release .zip or .hex file from the Meshtastic releases page.

   • Example using nrfutil:

     nrfutil dfu usb-serial -pkg firmware.zip -p /dev/ttyACM0

   • Replace /dev/ttyACM0 with the correct serial port.

6. Verify Flashing

   • After flashing, the device should reboot.
   • Use the Meshtastic app or CLI to connect and configure.

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💬 Community

Join the Michigan Meshtastic community on Discord:
https://discord.gg/jXtpzh4B

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📝 License

This project is released under a Non-Commercial Open Source License.
You are free to use, modify, and share this design for non-commercial purposes only.
Commercial use requires explicit permission from the author.

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✅ Tip: For more detailed instructions, see meshtastic.org/docs.

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