Dht22 sensor readings always zero

purpleapple · December 12, 2023, 1:29pm

Hi!

I'm facing an issue with my code where the output (temperature and humidity) consistently remains at zero. Here's my code:

/*******************************************************************************

Copyright (c) 2015 Thomas Telkamp and Matthijs Kooijman
Copyright (c) 2018 Terry Moore, MCCI
Permission is hereby granted, free of charge, to anyone
obtaining a copy of this document and accompanying files,
to do whatever they want with them without any restriction,
including, but not limited to, copying, modification and redistribution.
NO WARRANTY OF ANY KIND IS PROVIDED.
This example sends a valid LoRaWAN packet with payload "Hello,
world!", using frequency and encryption settings matching those of
the The Things Network. It's pre-configured for the Adafruit
Feather M0 LoRa.
This uses OTAA (Over-the-air activation), where where a DevEUI and
application key is configured, which are used in an over-the-air
activation procedure where a DevAddr and session keys are
assigned/generated for use with all further communication.
Note: LoRaWAN per sub-band duty-cycle limitation is enforced (1% in
g1, 0.1% in g2), but not the TTN fair usage policy (which is probably
violated by this sketch when left running for longer)!
To use this sketch, first register your application and device with
the things network, to set or generate an AppEUI, DevEUI and AppKey.
Multiple devices can use the same AppEUI, but each device has its own
DevEUI and AppKey.
Do not forget to define the radio type correctly in
arduino-lmic/project_config/lmic_project_config.h or from your BOARDS.txt.

*******************************************************************************/

#include <lmic.h>
#include <hal/hal.h>
#include <SPI.h>
#include <DHT.h>
#include <DHT_U.h>

// This EUI must be in little-endian format, so least-significant-byte
// first. When copying an EUI from ttnctl output, this means to reverse
// the bytes. For TTN issued EUIs the last bytes should be 0xD5, 0xB3,
// 0x70.
static const u1_t PROGMEM APPEUI[8]= { 0x34, 0x34, 0x34, 0x12, 0x12, 0x12, 0x12, 0x12 };
void os_getArtEui (u1_t* buf) { memcpy_P(buf, APPEUI, 8);}

// This should also be in little endian format, see above.
static const u1_t PROGMEM DEVEUI[8]= { 0xF0, 0x21, 0x00, 0xD8, 0x7E, 0xD5, 0xB3, 0x70 };
void os_getDevEui (u1_t* buf) { memcpy_P(buf, DEVEUI, 8);}

// This key should be in big endian format (or, since it is not really a
// number but a block of memory, endianness does not really apply). In
// practice, a key taken from the TTN console can be copied as-is.
static const u1_t PROGMEM APPKEY[16] = { 0x01, 0x7F, 0x12, 0x8B, 0xC8, 0x32, 0x73, 0x2D, 0x0F, 0xFC, 0x38, 0x0C, 0x98, 0x8B, 0xD4, 0x0D };
void os_getDevKey (u1_t* buf) { memcpy_P(buf, APPKEY, 16);}

static uint8_t mydata[] = "Hello, world!";
static osjob_t sendjob;

// Schedule TX every this many seconds (might become longer due to duty
// cycle limitations).
const unsigned TX_INTERVAL = 20;

// Pin mapping
//# error "Unknown target"
const lmic_pinmap lmic_pins = {
.nss = 10,
.rxtx = LMIC_UNUSED_PIN,
.rst = 9,
.dio = {3,4,5},
.rxtx_rx_active = 0,
.rssi_cal = 0, // LBT cal for in dB
.spi_freq = 1000000
};

#define DHT_PIN 7
#define DHTTYPE DHT22
DHT dht(DHT_PIN, DHTTYPE);

void onEvent (ev_t ev) {
Serial.print(os_getTime());
Serial.print(": ");
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"));
{
u4_t netid = 0;
devaddr_t devaddr = 0;
u1_t nwkKey[16];
u1_t artKey[16];
LMIC_getSessionKeys(&netid, &devaddr, nwkKey, artKey);
Serial.print("netid: ");
Serial.println(netid, DEC);
Serial.print("devaddr: ");
Serial.println(devaddr, HEX);
Serial.print("artKey: ");
for (int i=0; i<sizeof(artKey); ++i) {
if (i != 0)
Serial.print("-");
Serial.print(artKey[i], HEX);
}
Serial.println("");
Serial.print("nwkKey: ");
for (int i=0; i<sizeof(nwkKey); ++i) {
if (i != 0)
Serial.print("-");
Serial.print(nwkKey[i], HEX);
}
Serial.println("");
}
// Disable link check validation (automatically enabled
// during join, but because slow data rates change max TX
// size, we don't use it in this example.
LMIC_setLinkCheckMode(0);
break;
/*
|| This event is defined but not used in the code. No
|| point in wasting codespace on it.
||
|| 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;
break;
case EV_TXCOMPLETE:
Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
if (LMIC.txrxFlags & TXRX_ACK)
Serial.println(F("Received ack"));
if (LMIC.dataLen) {
Serial.print(F("Received "));
Serial.print(LMIC.dataLen);
Serial.println(F(" bytes of payload"));
Serial.print("Port: ");
Serial.println(LMIC.frame[(LMIC.dataBeg-1)]);
Serial.print("Data: ");
// char rec_data = (LMIC.frame + LMIC.dataBeg);
for (int i=0; i< LMIC.dataLen; ++i) {
if (i != 0)
Serial.print(",");
Serial.print(LMIC.frame[LMIC.dataBeg+i], HEX);
}
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;
/
|| This event is defined but not used in the code. No
|| point in wasting codespace on it.
||
|| case EV_SCAN_FOUND:
|| Serial.println(F("EV_SCAN_FOUND"));
|| break;
*/
case EV_TXSTART:
Serial.println(F("EV_TXSTART"));
break;
default:
Serial.print(F("Unknown event: "));
Serial.println((unsigned) ev);
break;
}
}

void do_send(osjob_t* j){
// Check if there is not a current TX/RX job running
if (LMIC.opmode & OP_TXRXPEND) {
Serial.println(F("OP_TXRXPEND, not sending"));
} else {
uint32_t humidity = dht.readHumidity(false)*100;
uint32_t temperature = dht.readTemperature(false) * 100;

    Serial.println("Humidity: " + String(humidity));
    Serial.println("Temperature: " + String(temperature));
    
    byte payload[4];
    payload[0] = highByte(humidity);
    payload[1] = lowByte(humidity);
    payload[2] = highByte(temperature);
    payload[3] = lowByte(temperature); 
  
    // Prepare upstream data transmission at the next possible time.
    LMIC_setTxData2(3, (xref2u1_t)(payload), sizeof(payload), 0);
    Serial.println(F("Packet queued"));
}
// Next TX is scheduled after TX_COMPLETE event.

}

void setup() {
delay(5000);
while (! Serial)
;
Serial.begin(9600);
Serial.println(F("Starting"));

#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);

LMIC_setLinkCheckMode(0);
LMIC_setDrTxpow(DR_SF7,14);

// Start job (sending automatically starts OTAA too)
do_send(&sendjob);

}

void loop() {
os_runloop_once();
}

Despite several attempts, I can't figure out why the output stays zero. Any insights or suggestions on debugging this would be great.

Thanks!

purpleapple · December 12, 2023, 2:11pm

In addition, can we ask for the format of the payload as well?

jim-p · December 12, 2023, 2:17pm

Please post your code using code tags <code>

purpleapple · December 12, 2023, 2:59pm

/*******************************************************************************
 * Copyright (c) 2015 Thomas Telkamp and Matthijs Kooijman
 * Copyright (c) 2018 Terry Moore, MCCI
 *
 * Permission is hereby granted, free of charge, to anyone
 * obtaining a copy of this document and accompanying files,
 * to do whatever they want with them without any restriction,
 * including, but not limited to, copying, modification and redistribution.
 * NO WARRANTY OF ANY KIND IS PROVIDED.
 *
 * This example sends a valid LoRaWAN packet with payload "Hello,
 * world!", using frequency and encryption settings matching those of
 * the The Things Network. It's pre-configured for the Adafruit
 * Feather M0 LoRa.
 *
 * This uses OTAA (Over-the-air activation), where where a DevEUI and
 * application key is configured, which are used in an over-the-air
 * activation procedure where a DevAddr and session keys are
 * assigned/generated for use with all further communication.
 *
 * Note: LoRaWAN per sub-band duty-cycle limitation is enforced (1% in
 * g1, 0.1% in g2), but not the TTN fair usage policy (which is probably
 * violated by this sketch when left running for longer)!

 * To use this sketch, first register your application and device with
 * the things network, to set or generate an AppEUI, DevEUI and AppKey.
 * Multiple devices can use the same AppEUI, but each device has its own
 * DevEUI and AppKey.
 *
 * Do not forget to define the radio type correctly in
 * arduino-lmic/project_config/lmic_project_config.h or from your BOARDS.txt.
 *
 *******************************************************************************/

#include <lmic.h>
#include <hal/hal.h>
#include <SPI.h>
#include <DHT.h>
#include <DHT_U.h>


// This EUI must be in little-endian format, so least-significant-byte
// first. When copying an EUI from ttnctl output, this means to reverse
// the bytes. For TTN issued EUIs the last bytes should be 0xD5, 0xB3,
// 0x70.
static const u1_t PROGMEM APPEUI[8]= { 0x34, 0x34, 0x34, 0x12, 0x12, 0x12, 0x12, 0x12 };
void os_getArtEui (u1_t* buf) { memcpy_P(buf, APPEUI, 8);}

// This should also be in little endian format, see above.
static const u1_t PROGMEM DEVEUI[8]= { 0xF0, 0x21, 0x00, 0xD8, 0x7E, 0xD5, 0xB3, 0x70 };
void os_getDevEui (u1_t* buf) { memcpy_P(buf, DEVEUI, 8);}

// This key should be in big endian format (or, since it is not really a
// number but a block of memory, endianness does not really apply). In
// practice, a key taken from the TTN console can be copied as-is.
static const u1_t PROGMEM APPKEY[16] = { 0x01, 0x7F, 0x12, 0x8B, 0xC8, 0x32, 0x73, 0x2D, 0x0F, 0xFC, 0x38, 0x0C, 0x98, 0x8B, 0xD4, 0x0D };
void os_getDevKey (u1_t* buf) {  memcpy_P(buf, APPKEY, 16);}

static uint8_t mydata[] = "Hello, world!";
static osjob_t sendjob;

// Schedule TX every this many seconds (might become longer due to duty
// cycle limitations).
const unsigned TX_INTERVAL = 20;

// Pin mapping
//# error "Unknown target"
const lmic_pinmap lmic_pins = {
    .nss = 10, 
    .rxtx = LMIC_UNUSED_PIN,
    .rst = 9,
    .dio = {3,4,5}, 
    .rxtx_rx_active = 0,
    .rssi_cal = 0,              // LBT cal for in dB
    .spi_freq = 1000000
};

#define DHT_PIN 7
#define DHTTYPE DHT22
DHT dht(DHT_PIN, DHTTYPE);

void onEvent (ev_t ev) {
    Serial.print(os_getTime());
    Serial.print(": ");
    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"));
            {
              u4_t netid = 0;
              devaddr_t devaddr = 0;
              u1_t nwkKey[16];
              u1_t artKey[16];
              LMIC_getSessionKeys(&netid, &devaddr, nwkKey, artKey);
              Serial.print("netid: ");
              Serial.println(netid, DEC);
              Serial.print("devaddr: ");
              Serial.println(devaddr, HEX);
              Serial.print("artKey: ");
              for (int i=0; i<sizeof(artKey); ++i) {
                if (i != 0)
                  Serial.print("-");
                Serial.print(artKey[i], HEX);
              }
              Serial.println("");
              Serial.print("nwkKey: ");
              for (int i=0; i<sizeof(nwkKey); ++i) {
                      if (i != 0)
                              Serial.print("-");
                      Serial.print(nwkKey[i], HEX);
              }
              Serial.println("");
            }
            // Disable link check validation (automatically enabled
            // during join, but because slow data rates change max TX
      // size, we don't use it in this example.
            LMIC_setLinkCheckMode(0);
            break;
        /*
        || This event is defined but not used in the code. No
        || point in wasting codespace on it.
        ||
        || 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;
            break;
        case EV_TXCOMPLETE:
            Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
            if (LMIC.txrxFlags & TXRX_ACK)
              Serial.println(F("Received ack"));
            if (LMIC.dataLen) {
              Serial.print(F("Received "));
              Serial.print(LMIC.dataLen);
              Serial.println(F(" bytes of payload"));
              Serial.print("Port: ");
              Serial.println(LMIC.frame[(LMIC.dataBeg-1)]);
              Serial.print("Data: ");
             // char rec_data = (LMIC.frame + LMIC.dataBeg);
              for (int i=0; i< LMIC.dataLen; ++i) {
                if (i != 0)
                  Serial.print(",");
                Serial.print(LMIC.frame[LMIC.dataBeg+i], HEX);
              }
              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;
        /*
        || This event is defined but not used in the code. No
        || point in wasting codespace on it.
        ||
        || case EV_SCAN_FOUND:
        ||    Serial.println(F("EV_SCAN_FOUND"));
        ||    break;
        */
        case EV_TXSTART:
            Serial.println(F("EV_TXSTART"));
            break;
        default:
            Serial.print(F("Unknown event: "));
            Serial.println((unsigned) ev);
            break;
    }
}

void do_send(osjob_t* j){
    // Check if there is not a current TX/RX job running
    if (LMIC.opmode & OP_TXRXPEND) {
        Serial.println(F("OP_TXRXPEND, not sending"));
    } else {
        uint32_t humidity = dht.readHumidity(false)*100;
        uint32_t temperature = dht.readTemperature(false) * 100;
        
        Serial.println("Humidity: " + String(humidity));
        Serial.println("Temperature: " + String(temperature));
        
        byte payload[4];
        payload[0] = highByte(humidity);
        payload[1] = lowByte(humidity);
        payload[2] = highByte(temperature);
        payload[3] = lowByte(temperature); 
      
        // Prepare upstream data transmission at the next possible time.
        LMIC_setTxData2(3, (xref2u1_t)(payload), sizeof(payload), 0);
        Serial.println(F("Packet queued"));
    }
    // Next TX is scheduled after TX_COMPLETE event.
}

void setup() {
    delay(5000);
    while (! Serial)
        ;
    Serial.begin(9600);
    Serial.println(F("Starting"));

    #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);

    LMIC_setLinkCheckMode(0);
    LMIC_setDrTxpow(DR_SF7,14);

    // Start job (sending automatically starts OTAA too)
    do_send(&sendjob);
}

void loop() {
    os_runloop_once();
}

purpleapple · December 12, 2023, 3:02pm

here's the formatter code i used in ttn

 function Decoder(bytes, port) {
    var decoded = {};

    if (port === 1) {
        decoded.message = String.fromCharCode.apply(null, bytes);
    }

    else if (port === 3) {
        var data = bytes;
        decoded.hum = (data[0] << 8 | data[1])/100;
        decoded.temp = (data[2] << 8 | data[3])/100;
        }
    // Return decoded object
    return decoded;
}

system · June 9, 2024, 3:02pm

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Dht22 sensor readings always zero

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