NodeMCU lua library for LoRa SX1276/SX1278 radio communication modules
The library is a based on the library from https://github.com/JaapBraam/LoRaWanGateway
The improvements:
- fixed a bug with incorrect operations on message buffers which result in sending garbage instead of actual message
- enhanced power management to support 20dBm mode
- implementation was inspired by https://github.com/sandeepmistry/arduino-LoRa/blob/master/src/LoRa.cpp
I'm not an expert in implementing such libraries and I don't understand most of these registers operations, but I made it work for me somehow 😃
Most of the credits goes to authors of the mentioned libraries who had to study SX1276 manual a lot 🧐
local radioLib = require('sx1276.lua')
local nssPin = 0
local dio0Pin = 1
local dio1Pin = 2
local frequency = 433.000 * 1000000 -- Frequency in Hz
local spreadingFactor = "SF7" -- "SF7" - "SF12"
local bandWidth = "BW125" -- I think only this one is supported
local errorCorrection = "4/5" -- I believe these are supported: "4/5", "4/6", "4/7", "4/8"
local radioInterface = radioLib(
nssPin,
dio0Pin,
dio1Pin,
frequency,
spreadingFactor,
bandWidth,
errorCorrection
)
-- Receiving
local function handleMessage(pkt)
print("RX!")
print("Data: ", pkt.data)
print("RSSI: ", pkt.rssi)
for k, v in pairs(pkt) do
print(k, v)
end
end
radioInterface.rxpk = handleMessage
-- Transmitting
local pkt = {
freq = frequency,
codr = errorCorrection,
datr = spreadingFactor .. bandWidth,
data = "Here goes your message",
powe = 17 -- values 0..20
}
radio.txpk(pkt)
Stolen from https://github.com/JaapBraam/LoRaWanGateway/blob/master/README.md#hardware
| ESP PIN | SX1276 PIN |
|---|---|
| D1 (GPIO5) | DIO0 |
| D2 (GPIO4) | DIO1 |
| D5 (GPIO14) | SCK |
| D6 (GPIO12) | MISO |
| D7 (GPIO13) | MOSI |
| D0 (GPIO16) | NSS |
| GND | GND |
| 3.3V | VCC |
The library needs a lot of refactoring, feel free to open a PR!
- refactor global variables with register numbers into object with all registers
- refactor all register magic numbers to variables with register numbers
- remove code responsible for handling multiple spreading factors
- make the API more friendly
- implement support for low power mode - right now NodeMCU has to be ON all the time to handle incoming messages, but there is a way to use interrupts from SX1276 to wake up NodeMCU