SX1278 MicroPython Library for Raspberry Pi Pico

Lightweight MicroPython driver for the Ra-01 LoRa module based on the SX1278 chipset, with a setup focused on the Raspberry Pi Pico (RP2040) and Raspberry Pi Pico 2 (RP2350).

The library communicates over SPI and provides a simple API for sending and receiving LoRa packets.

Features

• MicroPython-first API with minimal setup
• Works with Raspberry Pi Pico and Pico 2
• Blocking packet transmission with send()
• Interrupt-driven packet reception with on_recv()
• Configurable frequency, bandwidth, spreading factor, coding rate, and CRC

Installation

Copy sx1278.py to the root of your MicroPython device, then import it in your script:

from sx1278 import Lora

Quick Start

Example wiring used by the snippets below:

SX1278 / Ra-01	Raspberry Pi Pico	Used in code
MISO	GP0	MISO = 0
DIO0	GP10	RX = 10
SCK	GP2	SCK = 2
MOSI	GP3	MOSI = 3
RST	GP16	RST = 16
NSS	GP1	CS = 1
GND	GND	power
3V3	3V3(OUT)	power

Set up SPI first:

from machine import Pin, SPI
from sx1278 import Lora

SCK = 2
MOSI = 3
MISO = 0
CS = 1
RX = 10
RST = 16

spi = SPI(
    0,
    baudrate=10_000_000,
    sck=Pin(SCK, Pin.OUT, Pin.PULL_DOWN),
    mosi=Pin(MOSI, Pin.OUT, Pin.PULL_UP),
    miso=Pin(MISO, Pin.IN, Pin.PULL_UP),
)
spi.init()

Then create the LoRa instance:

lr = Lora(
    spi,
    cs=Pin(CS, Pin.OUT),
    rx=Pin(RX, Pin.IN),
    rs=Pin(RST, Pin.OUT),
)

Sending Data

send() blocks until transmission has finished. The maximum payload length is 255 bytes.

lr.send("Hello World!")

Receiving Data

Register a receive handler, put the module into receive mode, and keep the script running:

def handler(message):
    print(message)
    # Put the module back into receive mode after handling a packet.
    lr.recv()

lr.on_recv(handler)
lr.recv()

while True:
    pass

Examples

Ready-to-run examples for the Raspberry Pi Pico are included in the example directory:

• example/send.py
• example/receive.py

Important Notes

• Use a frequency that is legal for your region.
• The default frequency in sx1278.py is 433.1 MHz.
• You can override the default by passing frequency= when creating Lora, or by changing the module constant in the library.

License

This project is licensed under the MIT License. See LICENSE.