Deki LoRa

LoRa radio for the Deki Engine: a driver for the Semtech SX1262 that sends and receives packets, with a duty-cycle limit built in.

Part of Deki Engine.

Use

Add SX1262 LoRa (DekiLora::SX1262LoRaComponent) to the board's boot scene with its wiring and radio settings. Game code then reaches the radio through DekiLora::DekiLoRa::GetCurrent(), which is nullptr on a board without one or when it did not answer:

#include "DekiLoRa.h"  // from deki-lora

if (auto* radio = DekiLora::DekiLoRa::GetCurrent())
{
    const char text[] = "hello";
    if (radio->MillisecondsUntilCanSend() == 0)
    {
        radio->Send(reinterpret_cast<const uint8_t*>(text), sizeof(text) - 1);
    }

    DekiLora::LoRaPacket packet;
    while (radio->Receive(packet))
    {
        // packet.data, packet.rssi (dBm), packet.snr (dB)
    }
}

The radio listens whenever it is not sending; received packets queue (the last 8) until read.

Frequency, power and duty cycle

Radio use is regulated. Set the frequency, power and duty cycle your region allows. The defaults are Europe's 868.0-868.6 MHz sub-band: 868.1 MHz, 14 dBm, 1% duty cycle. In the Americas use 902-928 MHz (915 MHz).

The duty cycle is enforced: after a packet that took T on air, Send() refuses for T × (100 / duty − 1). At SF7 and 125 kHz a 16-byte packet takes about 50 ms, so at 1% the next may go about 5 s later. MillisecondsUntilCanSend() says how long is left.

Boards

On the LilyGO T-Deck and T-Deck Plus the SX1262 shares the display's SPI bus: SCK 40, MOSI 41, MISO 38, CS 9, BUSY 13, RESET 17, a 1.8 V TCXO on DIO3, and DIO2 switching the antenna. Those are the component's defaults.

Only ESP-IDF builds have a driver. Elsewhere the component starts no radio, and GetCurrent() stays nullptr.

Namespace

Types live in DekiLora.

Community

Questions, ideas and what you made with Deki: the Deki Discord.