Monitoring UV index, ground temperature and humidity

#include <Arduino.h>
#include "LoRaWan-Arduino.h"
#include <SPI.h>
#include <Wire.h>
#include "UVlight_LTR390.h"
#include "RAK12035_SoilMoisture.h"

// ============================
// LoRaWAN Settings
// ============================
bool doOTAA = true;
#define LORAWAN_APP_PORT 2
#define LORAWAN_APP_INTERVAL 10000  // ms

DeviceClass_t g_CurrentClass = CLASS_A;
LoRaMacRegion_t g_CurrentRegion = LORAMAC_REGION_EU868;
lmh_confirm g_CurrentConfirm = LMH_UNCONFIRMED_MSG;

// OTAA keys
uint8_t nodeDeviceEUI[8] = {0xAC,0x1F,0x09,0xFF,0xFE,0x06,0xB5,0xFB};
uint8_t nodeAppEUI[8]    = {0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88};
uint8_t nodeAppKey[16]   = {0xA6,0x7D,0x91,0xEA,0xD1,0xB8,0x6B,0x66,0x61,0x91,0xB9,0xDC,0xDD,0x4A,0x53,0xDD};

// ============================
// LoRaWAN Buffers
// ============================
#define LORAWAN_APP_DATA_BUFF_SIZE 8
static uint8_t m_lora_app_data_buffer[LORAWAN_APP_DATA_BUFF_SIZE];
static lmh_app_data_t m_lora_app_data = {m_lora_app_data_buffer, 0, 0, 0, 0};

mbed::Ticker appTimer;

// ============================
// Forward declarations
// ============================
static void lorawan_has_joined_handler(void);
static void lorawan_join_failed_handler(void);
static void lorawan_rx_handler(lmh_app_data_t *app_data);
static void lorawan_confirm_class_handler(DeviceClass_t Class);
void tx_lora_periodic_handler(void);
void send_lora_frame(float uvi, uint8_t uvEmergency, uint8_t soilHumidity, int16_t soilTemp);

// ============================
// LoRa callbacks
// ============================
static lmh_callback_t g_lora_callbacks = {
    BoardGetBatteryLevel,
    BoardGetUniqueId,
    BoardGetRandomSeed,
    lorawan_rx_handler,
    lorawan_has_joined_handler,
    lorawan_confirm_class_handler,
    lorawan_join_failed_handler,
    nullptr,
    nullptr
};

// ============================
// Sensors
// ============================
UVlight_LTR390 ltr;
RAK12035 soilSensor;

// Calibration values for soil sensor
uint16_t zero_val = 73;
uint16_t hundred_val = 250;

// Soil readings
uint8_t soilHumidity = 0;
int16_t soilTemperature = 0;

// ============================
// Helpers
// ============================
void floatToBytes(float value, uint8_t* bytes) {
    union { float f; uint8_t b[4]; } u;
    u.f = value;
    for(int i=0;i<4;i++) bytes[i] = u.b[i];
}

// ============================
// Setup
// ============================
void setup() {
    Serial.begin(115200);
    while(!Serial){}

    pinMode(LED_BUILTIN, OUTPUT);
    pinMode(WB_IO2, OUTPUT);
    digitalWrite(WB_IO2, HIGH);
    delay(300);

    Wire.begin();

    // Init LTR390
    if(!ltr.init()){
        Serial.println("Couldn't find LTR390 sensor!");
        while(1) delay(1000);
    }
    ltr.setMode(LTR390_MODE_UVS);
    ltr.setGain(LTR390_GAIN_3);
    ltr.setResolution(LTR390_RESOLUTION_16BIT);

    // Init Soil Sensor
    soilSensor.begin();
    soilSensor.get_dry_cal(&zero_val);
    soilSensor.get_wet_cal(&hundred_val);

    // Init LoRa
    lora_rak11300_init();
    if(doOTAA){
        lmh_setDevEui(nodeDeviceEUI);
        lmh_setAppEui(nodeAppEUI);
        lmh_setAppKey(nodeAppKey);
    }
    lmh_param_t g_lora_param_init = {LORAWAN_ADR_ON, DR_0, LORAWAN_PUBLIC_NETWORK, 3, TX_POWER_5, LORAWAN_DUTYCYCLE_OFF};
    if(lmh_init(&g_lora_callbacks, g_lora_param_init, doOTAA, g_CurrentClass, g_CurrentRegion) != 0){
        Serial.println("lmh_init failed");
        return;
    }
    lmh_join();
}

// ============================
// Loop
// ============================
void loop() {
    float uvi = 0;
    uint8_t uvEmergency = 0;

    if(ltr.newDataAvailable()){
        uvi = ltr.getUVI();
        if(uvi >= 5.0){
            uvEmergency = 1;
        }
    }

    soilSensor.get_sensor_moisture(&soilHumidity);
    uint16_t tempRaw = 0;
    soilSensor.get_sensor_temperature(&tempRaw);
    soilTemperature = tempRaw / 10;

    send_lora_frame(uvi, uvEmergency, soilHumidity, soilTemperature);

    delay(LORAWAN_APP_INTERVAL);
}

// ============================
// Send LoRa Frame
// ============================
void send_lora_frame(float uvi, uint8_t uvEmergency, uint8_t soilHumidity, int16_t soilTemp){
    if(lmh_join_status_get() != LMH_SET) return;

    uint8_t i = 0;
    floatToBytes(uvi, &m_lora_app_data.buffer[i]); i+=4;
    m_lora_app_data.buffer[i++] = uvEmergency;
    m_lora_app_data.buffer[i++] = soilHumidity;
    m_lora_app_data.buffer[i++] = (soilTemp >> 8) & 0xFF;
    m_lora_app_data.buffer[i++] = soilTemp & 0xFF;

    m_lora_app_data.port = LORAWAN_APP_PORT;
    m_lora_app_data.buffsize = i;

    lmh_send(&m_lora_app_data, g_CurrentConfirm);
}

// ============================
// LoRa Handlers
// ============================
void lorawan_has_joined_handler(void){
    Serial.println("OTAA Network Joined!");
    lmh_class_request(g_CurrentClass);
    appTimer.attach(tx_lora_periodic_handler, std::chrono::milliseconds(LORAWAN_APP_INTERVAL));
}
void lorawan_join_failed_handler(void){ Serial.println("OTAA join failed!"); }
void lorawan_rx_handler(lmh_app_data_t *app_data){}
void lorawan_confirm_class_handler(DeviceClass_t Class){}
void tx_lora_periodic_handler(void){ appTimer.attach(tx_lora_periodic_handler, std::chrono::milliseconds(LORAWAN_APP_INTERVAL)); }