payload decoder on TTN

pema chowden on 18 Nov 2021
Latest activity Reply by pema chowden on 18 Nov 2021

i am trying to decode the below sketch to integrate TTNv3 to thingspeak.

can someone help me with this issue

#include <lmic.h>
#include <dht.h>
#include <hal/hal.h>
#include <SPI.h>
dht DHT;
#define DHT11_PIN 5
#define PIN_A A0
float temperature,humidity;      
float tem,hum;
unsigned int count = 1;        //For times count
String datastring1="";        
String datastring2="";        
String datastring3="";
static uint8_t mydata[11] = {0x01,0x67,0x00,0x00,0x02,0x68,0x00,0x03,0x65,0x00,0x00};
/* LoRaWAN NwkSKey, network session key
   This is the default Semtech key, which is used by the prototype TTN
   network initially.
   ttn*/
static const PROGMEM u1_t NWKSKEY[16] = { 0x72, 0x13, 0xF8, 0xF0, 0x9A, 0x3C, 0xF9, 0xE5, 0xE6, 0x01, 0xDA,0xAC, 0x32, 0xBA, 0x37 };
/* LoRaWAN AppSKey, application session key
   This is the default Semtech key, which is used by the prototype TTN
   network initially.
   ttn*/
static const u1_t PROGMEM APPSKEY[16] = { 0x2F, 0xF5, 0xF4, 0x08, 0x4E, 0x37, 0x20, 0x02, 0xBA, 0x2B, 0xED,  0x40, 0x24, 0xA2, 0x945 };
/*
 LoRaWAN end-device address (DevAddr)
 See http://thethingsnetwork.org/wiki/AddressSpace
 ttn*/
static const u4_t DEVADDR = 0x260D0CA5;
/* These callbacks are only used in over-the-air activation, so they are
  left empty here (we cannot leave them out completely unless
   DISABLE_JOIN is set in config.h, otherwise the linker will complain).*/
void os_getArtEui (u1_t* buf) { }
void os_getDevEui (u1_t* buf) { }
void os_getDevKey (u1_t* buf) { }
static osjob_t initjob,sendjob,blinkjob;
/* Schedule TX every this many seconds (might become longer due to duty
 cycle limitations).*/
const unsigned TX_INTERVAL = 10;
// Pin mapping
const lmic_pinmap lmic_pins = {
    .nss = 10,
    .rxtx = LMIC_UNUSED_PIN,
    .rst = 9,
    .dio = {2, 6, 7},
};
void do_send(osjob_t* j){
    // Check if there is not a current TX/RX job running
    if (LMIC.opmode & OP_TXRXPEND) {
        Serial.println("OP_TXRXPEND, not sending");
    } else {
          dhtTem();
          light();
          // Prepare upstream data transmission at the next possible time.
          //  LMIC_setTxData2(1,datasend,sizeof(datasend)-1,0);
          LMIC_setTxData2(1, mydata, sizeof(mydata), 0);
          Serial.println("Packet queued");
          Serial.print("LMIC.freq:");
          Serial.println(LMIC.freq);
          Serial.println("Receive data:");
      } 
      // Next TX is scheduled after TX_COMPLETE event.
  }
void onEvent (ev_t ev) {
    Serial.print(os_getTime());
    Serial.print(": ");
    Serial.println(ev);
    switch(ev) {
        case EV_SCAN_TIMEOUT:
            Serial.println(F("EV_SCAN_TIMEOUT"));
            break;
        case EV_BEACON_FOUND:
            Serial.println(F("EV_BEACON_FOUND"));
            break;
        case EV_BEACON_MISSED:
            Serial.println(F("EV_BEACON_MISSED"));
            break;
        case EV_BEACON_TRACKED:
            Serial.println(F("EV_BEACON_TRACKED"));
            break;
        case EV_JOINING:
            Serial.println(F("EV_JOINING"));
            break;
        case EV_JOINED:
            Serial.println(F("EV_JOINED"));
            break;
        case EV_RFU1:
            Serial.println(F("EV_RFU1"));
            break;
        case EV_JOIN_FAILED:
            Serial.println(F("EV_JOIN_FAILED"));
            break;
        case EV_REJOIN_FAILED:
            Serial.println(F("EV_REJOIN_FAILED"));
            break;
        case EV_TXCOMPLETE:
            Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
            if(LMIC.dataLen) {
                // data received in rx slot after tx
                Serial.print(F("Data Received: "));
                Serial.write(LMIC.frame+LMIC.dataBeg, LMIC.dataLen);
                Serial.println();
            }
            // Schedule next transmission
            os_setTimedCallback(&sendjob, os_getTime()+sec2osticks(TX_INTERVAL), do_send);
            break;
        case EV_LOST_TSYNC:
            Serial.println(F("EV_LOST_TSYNC"));
            break;
        case EV_RESET:
            Serial.println(F("EV_RESET"));
            break;
        case EV_RXCOMPLETE:
            // data received in ping slot
            Serial.println(F("EV_RXCOMPLETE"));
            break;
        case EV_LINK_DEAD:
            Serial.println(F("EV_LINK_DEAD"));
            break;
        case EV_LINK_ALIVE:
            Serial.println(F("EV_LINK_ALIVE"));
            break;
         default:
            Serial.println(F("Unknown event"));
            break;
    }
}
void setup() {
     // initialize digital pin  as an output.
      Serial.begin(9600);
      while(!Serial);
      Serial.println("Connect to TTN and Send data to mydevice(Use DHT11 Sensor):");
      #ifdef VCC_ENABLE
      // For Pinoccio Scout boards
      pinMode(VCC_ENABLE, OUTPUT);
      digitalWrite(VCC_ENABLE, HIGH);
      delay(1000);
      #endif
      // LMIC init
      os_init();
      // Reset the MAC state. Session and pending data transfers will be discarded.
      LMIC_reset();
      /*LMIC_setClockError(MAX_CLOCK_ERROR * 1/100);
       Set static session parameters. Instead of dynamically establishing a session
       by joining the network, precomputed session parameters are be provided.*/
      #ifdef PROGMEM
      /* On AVR, these values are stored in flash and only copied to RAM
         once. Copy them to a temporary buffer here, LMIC_setSession will
         copy them into a buffer of its own again.*/
      uint8_t appskey[sizeof(APPSKEY)];
      uint8_t nwkskey[sizeof(NWKSKEY)];
      memcpy_P(appskey, APPSKEY, sizeof(APPSKEY));
      memcpy_P(nwkskey, NWKSKEY, sizeof(NWKSKEY));
      LMIC_setSession (0x1, DEVADDR, nwkskey, appskey);
      #else
      // If not running an AVR with PROGMEM, just use the arrays directly 
      LMIC_setSession (0x1, DEVADDR, NWKSKEY, APPSKEY);
      #endif
       for (int channel=0; channel<8; ++channel) {
      LMIC_disableChannel(channel);
    }
    for (int channel=16; channel<72; ++channel) {
       LMIC_disableChannel(channel);
    }
      // Disable link check validation
      LMIC_setLinkCheckMode(0);
      // TTN uses SF9 for its RX2 window.
      LMIC.dn2Dr = DR_SF9;
      // Set data rate and transmit power (note: txpow seems to be ignored by the library)
      LMIC_setDrTxpow(DR_SF7,14);
      // Start job
      do_send(&sendjob);
  }
  void dhtTem()
  {
         int16_t tem1;
         temperature = DHT.read11(DHT11_PIN);    //Temperature detection
         tem = DHT.temperature*1.0;      
        float humidity = DHT.read11(DHT11_PIN);
        float hum = DHT.humidity* 1.0;
        Serial.print(F("###########    "));
         Serial.print(F("NO."));
         Serial.print(count);
         Serial.println(F("    ###########"));
         Serial.println(F("The temperautre and humidity :"));
         Serial.print(F("["));
         Serial.print(tem);
         Serial.print(F("℃"));
         Serial.print(F(","));
         Serial.print(hum);
         Serial.print(F("%"));
         Serial.print(F("]"));
         Serial.println("");
         count++;
         tem1=(tem*10);
         mydata[2] = tem1>>8;
         mydata[3]= tem1;
         mydata[6] = hum * 2;
}
void light(){
      int16_t lux;
      int val,val1;
      val=analogRead(PIN_A);
     // Serial.print(F("a:"));
      //Serial.println(val);
      delay(500);
      val1=val*1.0;
      lux=val1;
      mydata[9]=lux>>8;
      mydata[10]=lux;
       //Serial.print(lux);
}
void loop() {
    os_runloop_once();
}
Christopher Stapels
Christopher Stapels on 18 Nov 2021 (Edited on 18 Nov 2021)

See this video for some suggestions. What have you tried so far? What are you seeing?

pema chowden
pema chowden on 18 Nov 2021
function Decoder(bytes, port)
 {
   var tem = (bytes[2]<<8) | bytes[3];
   var hum = (bytes[6])*2;
     return {
        field3: tem,
        field4: hum
     }
  }
pema chowden
pema chowden on 18 Nov 2021

thank you, I tried the following decoder. i think I am reading the byte wrong