/RP2040-zero-SX1276-meshtastic

This repo contains the hardware and software development of a fixed node based on RP2040-Zero and SX127X (SX1276 and so) LoRa modules.

Primary LanguageC

RP2040-zero-meshtastic

This repo contains the hardware and software development of a fixed node based on RP2040-Zero and SX127X (SX1276 and so) LoRa modules.

Hardware

Parts needed:

  • RP2040-Zero
  • SX1276 Module
  • SSD1306 or similar I2C Oled screen compatible with Meshtastic.

Wiring

Wiring

SX127X GPIO SSD1306 (or similar) GPIO
SCK 10 VCC 3.3v
MOSI 11 GND GND
MISO 12 SDA 4
NSS/CS 3 SCL 5
DIO0 27
DIO1 29
DIO2 2
RST 15
VDD 3.3v
GND (any) GND

Note: Some boards as the TTGO Lora32 uses a 22 Ohm resistor between DIO0/DIO1 and their respective GPIOs. (Without this resistors works but if TTGO puts here, may be for a reason).

Firmware

You can use one of the precompiled firmware located into the firmware folder of this repo. With the method Drag and Drop shown here.

Build your own firmware

But if you want to build your own version, follow the steps below. ⬇️

As the same module used in the firmware precompiled by Meshtastic (rpico) is not this one (SX126X != SX127X), it is necessary to generate the binary ourselves. To do this, we must follow the steps outlined in this guide (it's not difficult but it takes some time).
Additionally, we need to add the following folder to the variants directory and modify the main platform.ini of the proyect as shown:

; PlatformIO Project Configuration File
; https://docs.platformio.org/page/projectconf.html

[platformio]
;default_envs = tbeam ; Comment this
;default_envs = pico
default_envs = rp2040-zero ; Add this
;default_envs = tbeam-s3-core
;default_envs = tbeam0.7
;default_envs = heltec-v1
;default_envs = heltec-v2_0

For compile, Ctrl + Shift + B or Ctrl + Shift + P. If all is SUCCESS, you have to upload it to the board.
I get failure every time in middle of the upload with the Upload button. To solve this, hold BOOT button of the RP2040-Zero and then connect to the PC, then copy in the folder that appears (like USB stick) the firmware.uf2 located in the meshtastic firmware repo folder: .pio/build/rp2040-zero/ (This appears when compilation was OK).

As soon as the copy ends, the board will reboot with the firmware installed. Then configure the region and check that there are no errors on the screen (or crash after 34 seconds if the radio is misconnected).

Other usefull stuff

The 3D printed case for this LoRa module

Here is the Thingiverse link.

Case