130 lines
4.1 KiB
Python
130 lines
4.1 KiB
Python
import time
|
|
import uuid
|
|
from sx1262 import SX1262
|
|
|
|
import uasyncio as asyncio
|
|
from queue import Queue
|
|
|
|
from machine import Pin
|
|
led = Pin(25, Pin.OUT)
|
|
|
|
class FixedDeque:
|
|
def __init__(self, maxlen):
|
|
self.maxlen = maxlen
|
|
self.data = []
|
|
|
|
def append(self, x):
|
|
if len(self.data) >= self.maxlen:
|
|
self.data.pop(0)
|
|
self.data.append(x)
|
|
|
|
def __iter__(self):
|
|
return iter(self.data)
|
|
|
|
class LoRaMessage:
|
|
def __init__(self, sender_id: str, recipient_id: str, payload: bytes):
|
|
self.sender_id = sender_id
|
|
self.recipient_id = recipient_id
|
|
self.payload = payload
|
|
self.message_id = str(uuid.uuid4())
|
|
self.lifetime = 7
|
|
|
|
def encode(self) -> bytes:
|
|
encoded = bytearray()
|
|
|
|
encoded.append(len(self.sender_id))
|
|
encoded.extend(self.sender_id.encode("utf-8"))
|
|
|
|
encoded.append(len(self.recipient_id))
|
|
encoded.extend(self.recipient_id.encode("utf-8"))
|
|
|
|
encoded.extend(self.payload)
|
|
|
|
return bytes(encoded)
|
|
|
|
@staticmethod
|
|
def decode(data: bytes):
|
|
sender_id_len = data[0]
|
|
sender_id = data[1:1+sender_id_len].decode("utf-8")
|
|
|
|
recipient_id_len = data[1+sender_id_len]
|
|
recipient_id = data[2+sender_id_len:2+sender_id_len+recipient_id_len].decode("utf-8")
|
|
|
|
payload = data[2+sender_id_len+recipient_id_len:]
|
|
|
|
return LoRaMessage(sender_id=sender_id, recipient_id=recipient_id, payload=payload)
|
|
|
|
class LoRaHandler:
|
|
def __init__(self):
|
|
print("Initializing LoRa...")
|
|
|
|
self.my_id = str(uuid.uuid4())
|
|
|
|
# initialize our radio, im using the HAT SX1262 hat for the pico
|
|
self.radio = SX1262(spi_bus=1, clk=10, mosi=11, miso=12, cs=3, irq=20, rst=15, gpio=2)
|
|
self.radio.begin(freq=915, bw=125, power=22)
|
|
self.radio.setBlockingCallback(False, self.irq)
|
|
|
|
self.recent_messages = FixedDeque(32)
|
|
self.neighbours = set()
|
|
self.message_queue = Queue()
|
|
|
|
def send(self, data: bytes, recipient_id: str):
|
|
msg_bytes = LoRaMessage(sender_id=self.my_id, recipient_id=recipient_id, payload=data).encode()
|
|
self.radio.send(msg_bytes)
|
|
|
|
def forward(self, msg: LoRaMessage):
|
|
msg_bytes = msg.encode()
|
|
self.radio.send(msg_bytes)
|
|
|
|
def advertise(self):
|
|
# send an advertisement message to let neighbors know we're here
|
|
self.send(b"ADVERTISE", recipient_id="BROADCAST")
|
|
|
|
def on_receive(self, msg: LoRaMessage):
|
|
# ensure we don't process a message twice
|
|
if msg.message_id in self.recent_messages:
|
|
return
|
|
self.recent_messages.append(msg.message_id)
|
|
|
|
# messages has a lifetime to prevent infinite loops.
|
|
# if we receive a message with lifetime <= 0 we just drop it,
|
|
# otherwise we decrement the lifetime and forward it to all
|
|
# neighbors except the sender
|
|
msg.lifetime -= 1
|
|
if msg.lifetime <= 0:
|
|
return
|
|
|
|
# forward messages if they aren't meant for us
|
|
|
|
if (msg.recipient_id != self.my_id) and msg.recipient_id != "BROADCAST":
|
|
print("Forwarding message...")
|
|
self.forward(msg)
|
|
return
|
|
|
|
if msg.payload == b"ADVERTISE":
|
|
if not msg.sender_id in self.neighbours:
|
|
print(f"Neighbour discovered: {msg.sender_id}")
|
|
self.neighbours.add(msg.sender_id)
|
|
self.send(b"Ping!", msg.sender_id)
|
|
|
|
return
|
|
|
|
asyncio.create_task(self.message_queue.put(msg))
|
|
|
|
|
|
|
|
def irq(self, events):
|
|
#print(f"LORA EVENT: {events}")
|
|
if events & SX1262.RX_DONE:
|
|
msg, err = self.radio.recv()
|
|
error = SX1262.STATUS[err]
|
|
|
|
if error != "ERR_NONE":
|
|
print(f"Error receiving message: {error}")
|
|
return
|
|
|
|
self.on_receive(LoRaMessage.decode(msg))
|
|
elif events & SX1262.TX_DONE:
|
|
pass
|
|
#print('TX done.') |