Hi,
I’m new on CayenneLpp world.
Using RFM95W SX1276 as sender and TTGO LoRa32 as receiver, with sandeepmistry/LoRa@^0.7.2 library.
Sending multiple sensor’s data (temp, hum, luminance), how to read and decode the complete LoRa message on receiver ?
Thank’s
there is an example for receiver arduino-LoRa/LoRaReceiver.ino at master · sandeepmistry/arduino-LoRa · GitHub
Sorry, I know this sample, but it is too simple… 
I’m using the CayenneLPP message protocol to send and receive the data.
Did you try the code? what are you receiving?
Hi shramik,
this is the Sender code :
if (LoRa.beginPacket())
{
LoRa.write(lpp.getBuffer(), lpp.getSize());
if (LoRa.endPacket())
{
Serial.println("Lora Transmission OK");
}
else
{
Serial.println("Lora Transmission Error");
}
}
else
{
Serial.println("Lora Transmission Error");
}
Serial.print("Bytes sent : ");
Serial.println(lpp.getSize());
uint8_t *payload = lpp.getBuffer();
for (unsigned char i = 0; i < lpp.getSize(); i++)
{
Serial.print("0x");
Serial.print(payload[i], HEX);
Serial.print(" ");
}
// print checkmark
Serial.println();
Serial.print("LoRa message sent \u2714\r\n");
// DECODE
// uint8_t *payload = lpp.getBuffer();
StaticJsonDocument<512> jsonBuffer;
JsonArray root = jsonBuffer.to<JsonArray>();
lpp.decode(lpp.getBuffer(), lpp.getSize(), root);
serializeJsonPretty(root, Serial);
Serial.println();
…
This is the sender code result
Bytes sent : 11
0x1 0x67 0x0 0xD4 0x2 0x68 0x4A 0x3 0x74 0x1 0xF6
LoRa message sent ✔
[
{
"channel": 1,
"type": 103,
"name": "temperature",
"value": 21.2
},
{
"channel": 2,
"type": 104,
"name": "humidity",
"value": 37
},
{
"channel": 3,
"type": 116,
"name": "voltage",
"value": 5.02
}
]
Then, the receiver code
…
uint8_t *payload;
int packetSize = LoRa.parsePacket();
if (packetSize)
{
// received a packet
Serial.printf("Received %i bytes, RSSI : %i ", packetSize, LoRa.packetRssi());
while (LoRa.available())
{
payload += (uint8_t)LoRa.read();
}
// print checkmark
Serial.printf(" \u2714\r\n");
for (unsigned char i = 0; i < packetSize; i++)
{
Serial.print("0x");
Serial.print(payload[i], HEX);
Serial.print(" ");
}
Serial.println();
Serial.print("|");
for (unsigned int i = 0; i < packetSize; i++)
{
Serial.print(payload[i] >> 4, HEX);
Serial.print(payload[i] & 0xF, HEX);
}
Serial.print("|");
Serial.println();
The received message is
Received 11 bytes, RSSI : -62 ✔
0x45 0x3E 0x0 0x42 0x7F 0x40 0x0 0x72 0x49 0x49 0x49
|453E00427F400072494949|
Received 11 bytes, RSSI : -62 ✔
0xF 0x38 0x44 0x44 0x38 0x44 0xFC 0x4A 0x4A 0x4A 0x34
|0F3844443844FC4A4A4A34|
Received 11 bytes, RSSI : -62 ✔
0xF0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x1F 0xF8 0x7F
|F0000000000000001FF87F|
My question are :
#1. How to read correcty data on this case
#2. How to print on serial correctly data for debugging (there are two temptatives, are correct there ?)
#3. How to decode CayennLPP message from a payload
#4. How to extract a single value (e.g. temperature, or voltage) from received message
Many thanks to all.
The received message does not look like the cayenneLPP format.
can you try:-
void loop() {
// see if a packet was received
int packetSize = LoRa.parsePacket();
if (packetSize) {
// received packet
Serial.println(”“);
Serial.println(“Received packet: “);
// read the packet
String message = ”“;
while (LoRa.available()) {
message += (char)LoRa.read();
}
// print the Packet and RSSI
Serial.println(message);
Serial.print(“RSSI: “);
Serial.println(LoRa.packetRssi());
}
}No, the received message is always another content.
Message sent
Lora Transmission OK ✔ Bytes sent : 11 | 01 67 00 F6 02 68 41 03 74 01 F1 |
Message received
Received 11 bytes, RSSI : -59 ✔ | 41 53 4B 5F 57 44 54 5F 54 49 4D |
I’m struggling to understand.
Did you try the code i shared above? it is not the output it should give.
Can be the different architecture between Sender and Receiver ?
from my platformio.ini
Sender :
[env:sas-sender-struct]
platform = atmelavr
board = pro8MHzatmega328
Receiver
[env:ttgo-lora-receiver-dht11-struct]
platform = espressif32
board = ttgo-lora32-v1
Yes the code as you suggested :
while (LoRa.available())
{
payload += (char)LoRa.read();
}
just replace this with your code.
? What ???
Surely, wait
while (LoRa.available())
{
payload = (char)LoRa.read();
}
ERROR
error: invalid conversion from 'char' to 'uint8_t* {aka unsigned char*}' [-fpermissive]
payload = (char)LoRa.read();
can you share the entire code.
Sorry, I missing the new definition of payload.
But defining payload as
char * payload;
the receiver crashing on receiving message.
This is entire code of receiver
void loop()
{
char * payload;
int packetSize = LoRa.parsePacket();
if (packetSize)
{
// received a packet
Serial.printf("Received %i bytes, RSSI : %i ", packetSize, LoRa.packetRssi());
// while (LoRa.available())
// {
// payload += (uint8_t)LoRa.read();
// }
while (LoRa.available())
{
payload = (char*)LoRa.read();
}
Serial.print(" | ");
for (unsigned int i = 0; i < packetSize; i++)
{
Serial.print(payload[i] >> 4, HEX);
Serial.print(payload[i] & 0xF, HEX);
Serial.print(" ");
}
Serial.print("|");
Serial.println();
// String testString = "3E7C3E1C183C7E3C181C57";
// uint8_t *buffer = (uint8_t *)testString.c_str();
// StaticJsonDocument<512> jsonBuffer;
// JsonArray root = jsonBuffer.to<JsonArray>();
// lpp.decode((uint8_t *)buffer, packetSize, root);
// serializeJsonPretty(root, Serial);
// Serial.println();
// payload.toCharArray(buf, packetSize + 1);
// Dump payload content for debugging
// Serial.printf ("LPP Buffer: %s\r\n", printHexBuffer ((uint8_t *)payload, packetSize));
// String buffera = "00000000000001670101026838037401F6";
// char buf[buffera.length()];
// buffera.toCharArray(buf, payload.length());
// lpp.decode((uint8_t *)buf, packetSize, root);
}
delay(10);
}
It should be a String.
can you just copy and paste the code with freq change.
#include <SPI.h>
#include <LoRa.h>
void setup() {
Serial.begin(9600);
while (!Serial);
Serial.println("LoRa Receiver Test");
// Replace the operating frequency of your shield here.
// 915E6 for North America, 868E6 for Europe, 433E6 for Asia
if (!LoRa.begin(868E6)) {
Serial.println("Starting LoRa failed!");
while (1);
}
}
void loop() {
// see if a packet was received
int packetSize = LoRa.parsePacket();
if (packetSize) {
// received packet
Serial.println("");
Serial.println("Received packet: ");
// read the packet
String message = "";
while (LoRa.available()) {
message += (char)LoRa.read();
}
// print the Packet and RSSI
Serial.println(message);
Serial.print("RSSI: ");
Serial.println(LoRa.packetRssi());
}
}GOOD ! It working now.
A question : why sending an array of bytes as is
uint8_t *payload = lpp.getBuffer();
I must receive a String ???
Thank’s, many thanks shramik.
This is the final result
Received 11 bytes, RSSI : -61 ✔ | 01 67 00 F9 02 68 41 03 74 01 F3 |
[
{
"channel": 1,
"type": 103,
"name": "temperature",
"value": 24.9
},
{
"channel": 2,
"type": 104,
"name": "humidity",
"value": 32.5
},
{
"channel": 3,
"type": 116,
"name": "voltage",
"value": 4.99
}
]
This is the working receiver code
void loop()
{
String payload = "";
int packetSize = LoRa.parsePacket();
if (packetSize)
{
// received a packet
Serial.printf("Received %i bytes, RSSI : %i ", packetSize, LoRa.packetRssi());
while (LoRa.available())
{
payload += (char)LoRa.read();
}
// print checkmark
Serial.printf(" \u2714 ");
Serial.print(" | ");
for (unsigned int i = 0; i < packetSize; i++)
{
Serial.print(payload[i] >> 4, HEX);
Serial.print(payload[i] & 0xF, HEX);
Serial.print(" ");
}
Serial.print("|");
Serial.println();
// convert String to bytes array
uint8_t *buffer = (uint8_t *)payload.c_str();
StaticJsonDocument<512> jsonBuffer;
JsonArray root = jsonBuffer.to<JsonArray>();
lpp.decode((uint8_t *)buffer, packetSize, root);
serializeJsonPretty(root, Serial);
Serial.println();
}
delay(10);
}