I have only 1 RFM95 module and I would like (for test purposes) to simultaneously send and receive messages using the same module. I am using the code for duplex Lora communication that comes with the lora library. I set the message destination to be like the source (see code below).
/*
LoRa Duplex communication
Sends a message every half second, and polls continually
for new incoming messages. Implements a one-byte addressing scheme,
with 0xFF as the broadcast address.
Uses readString() from Stream class to read payload. The Stream class'
timeout may affect other functuons, like the radio's callback. For an
created 28 April 2017
by Tom Igoe
*/
#include <SPI.h> // include libraries
#include <LoRa.h>
const int csPin = 15; // LoRa radio chip select
const int resetPin = 0; //D3 LoRa radio reset
const int irqPin = 4; //D2 change for your board; must be a hardware interrupt pin
String outgoing; // outgoing message
byte msgCount = 0; // count of outgoing messages
byte localAddress = 0xBB; // address of this device
byte destination = 0xBB; // destination to send to
long lastSendTime = 0; // last send time
int interval = 2000; // interval between sends
void setup() {
Serial.begin(9600); // initialize serial
while (!Serial);
Serial.println("LoRa Duplex");
// override the default CS, reset, and IRQ pins (optional)
LoRa.setPins(csPin, resetPin, irqPin);// set CS, reset, IRQ pin
if (!LoRa.begin(915E6)) { // initialize ratio at 915 MHz
Serial.println("LoRa init failed. Check your connections.");
while (true); // if failed, do nothing
}
Serial.println("LoRa init succeeded.");
}
void loop() {
if (millis() - lastSendTime > interval) {
String message = "HeLoRa World!"; // send a message
sendMessage(message);
Serial.println("Sending " + message);
lastSendTime = millis(); // timestamp the message
interval = random(2000) + 1000; // 2-3 seconds
}
// parse for a packet, and call onReceive with the result:
onReceive(LoRa.parsePacket());
}
void sendMessage(String outgoing) {
LoRa.beginPacket(); // start packet
LoRa.write(destination); // add destination address
LoRa.write(localAddress); // add sender address
LoRa.write(msgCount); // add message ID
LoRa.write(outgoing.length()); // add payload length
LoRa.print(outgoing); // add payload
LoRa.endPacket(); // finish packet and send it
msgCount++; // increment message ID
}
void onReceive(int packetSize) {
if (packetSize == 0) return;
// if there's no packet, return
// read packet header bytes:
int recipient = LoRa.read(); // recipient address
byte sender = LoRa.read(); // sender address
byte incomingMsgId = LoRa.read(); // incoming msg ID
byte incomingLength = LoRa.read(); // incoming msg length
String incoming = "";
while (LoRa.available()) {
incoming += (char)LoRa.read();
}
if (incomingLength != incoming.length()) { // check length for error
Serial.println("error: message length does not match length");
return; // skip rest of function
}
// if the recipient isn't this device or broadcast,
if (recipient != localAddress && recipient != 0xFF) {
Serial.println("This message is not for me.");
return; // skip rest of function
}
// if message is for this device, or broadcast, print details:
Serial.println("Received from: 0x" + String(sender, HEX));
Serial.println("Sent to: 0x" + String(recipient, HEX));
Serial.println("Message ID: " + String(incomingMsgId));
Serial.println("Message length: " + String(incomingLength));
Serial.println("Message: " + incoming);
Serial.println("RSSI: " + String(LoRa.packetRssi()));
Serial.println("Snr: " + String(LoRa.packetSnr()));
Serial.println();
}
The results is that sent messages "HeLoRa World!" are not received by the module. I wonder if I can play on the timing of send/receive to get the message ?
Any suggestion is appreciated.
