Korištenje Heltec WiFi LoRa 32 V3 za prijenos temperature pomoću DHT22 na 1,4 km

/*
This is a simple code to display text on the OLED display
WiFi LoRa 32 V3 ESP32 module
Written by Ahmad Shamshiri 02 April 2025
Watch full video explanation https://youtu.be/WkyQMXkQhE8
Resources page https://robojax.com/tutorial_view.php?id=387
*/
#include <Wire.h>               
#include "HT_SSD1306Wire.h"


static SSD1306Wire  display(0x3c, 500000, SDA_OLED, SCL_OLED, GEOMETRY_128_64, RST_OLED); // addr , freq , i2c group , resolution , rst


void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.println();
  VextON();
  delay(100);

  // Initialising the UI will init the display too.
  display.init();

  display.setFont(ArialMT_Plain_10);

}


void displayTemperature(double temperature, int unit) {
    display.clear();  // Clear display before new content
    
    // Line 1: "Temperature:" in 16pt font
    display.setTextAlignment(TEXT_ALIGN_LEFT);
    display.setFont(ArialMT_Plain_16);
    display.drawString(0, 0, "Temperature:");

    // Line 2: Temperature value in 24pt font
    display.setFont(ArialMT_Plain_24);
    
    // Format temperature with correct unit symbol
    String tempString = String(temperature, 1); // 1 decimal place
    switch(unit) {
        case 1:  tempString += "�C"; break;  // Celsius
        case 2:  tempString += "�F"; break;  // Fahrenheit
        default: tempString += "�U"; break;  // Unknown unit
    }
    
    display.drawString(0, 20, tempString);  // Display at Y=20 (below label)
    display.display();  // Update OLED
}



void VextON(void)
{
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, LOW);
}

void VextOFF(void) //Vext default OFF
{
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, HIGH);
}



void loop() {
  // clear the display
  display.clear();
  displayTemperature(23.5, 1); // Displays "23.5�C" /1
  delay(2000);

}

/*
written on March 27, 2025
written by Ahmad Shamshiri for www.Robojax.com
Transmits Temperature and Humidity over LoRa RF using ESP32 LoRA 32 V3 module.
and displays the information on the screen.
Watch full video explanation https://youtu.be/WkyQMXkQhE8
Resources page: https://robojax.com/tutorial_view.php?id=387
*/

#include <Wire.h>               
#include "HT_SSD1306Wire.h"
static SSD1306Wire  display(0x3c, 500000, SDA_OLED, SCL_OLED, GEOMETRY_128_64, RST_OLED); // addr , freq , i2c group , resolution , rst

#include <DHT.h>
#define DHTPIN 3         // GPIO21
#define DHTTYPE DHT22     // DHT22 (AM2302)

DHT dht(DHTPIN, DHTTYPE);

float tempC, tempF;
int humidity ;

  //1=C
  //2=F
  //3=C, Humidity //only for display not for transmission
  //4=F, Humidity //only for display not for transmission
  //5=Humidity only
int dataType = 2;
String labelTemp = "Temperature";
String labelHumidity = "Humidity";
const int TX_POWER = 2;//dBm from 2 to 20. when powered via battery 2 to 14dBm is the best option

#include "mbedtls/aes.h"
#include <cstring>  // For memset, memcpy
mbedtls_aes_context aes;
const char *userKey = "hyhT676#h~_876s"; //Security key. 


#include "LoRaWan_APP.h"
#include "Arduino.h"


#define RF_FREQUENCY                                915000000 // Hz

#define TX_OUTPUT_POWER                             TX_POWER        // dBm from 2 to 20. when powered via battery 2 to 14dBm

#define LORA_BANDWIDTH                              0         // [0: 125 kHz,
                                                              //  1: 250 kHz,
                                                              //  2: 500 kHz,
                                                              //  3: Reserved]
#define LORA_SPREADING_FACTOR                       7         // [SF7..SF12]
#define LORA_CODINGRATE                             1         // [1: 4/5,
                                                              //  2: 4/6,
                                                              //  3: 4/7,
                                                              //  4: 4/8]
#define LORA_PREAMBLE_LENGTH                        8         // Same for Tx and Rx
#define LORA_SYMBOL_TIMEOUT                         0         // Symbols
#define LORA_FIX_LENGTH_PAYLOAD_ON                  false
#define LORA_IQ_INVERSION_ON                        false


#define RX_TIMEOUT_VALUE                            1000
#define BUFFER_SIZE                                 30 // Define the payload size here

char txpacket[BUFFER_SIZE];
char rxpacket[BUFFER_SIZE];

double txNumber;

bool lora_idle=true;

static RadioEvents_t RadioEvents;
unsigned long lastTxTime = 0;
void OnTxDone( void );
void OnTxTimeout( void );
void decryptAES(uint8_t *data, const char *key);
void encryptAES(uint8_t *data, const char *key);
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize);

void setup() {
  Serial.begin(115200);
  Serial.println();

  VextON();
  delay(100);

  // Initialising the UI will init the display too.
  display.init();

  display.setFont(ArialMT_Plain_10);
   dht.begin();

  //LoRa stuff
  Mcu.begin(HELTEC_BOARD,SLOW_CLK_TPYE);
	
    txNumber=0;

    RadioEvents.TxDone = OnTxDone;
    RadioEvents.TxTimeout = OnTxTimeout;
    
    Radio.Init( &RadioEvents );
    Radio.SetChannel( RF_FREQUENCY );
    Radio.SetTxConfig( MODEM_LORA, TX_OUTPUT_POWER, 0, LORA_BANDWIDTH,
                                   LORA_SPREADING_FACTOR, LORA_CODINGRATE,
                                   LORA_PREAMBLE_LENGTH, LORA_FIX_LENGTH_PAYLOAD_ON,
                                   true, 0, 0, LORA_IQ_INVERSION_ON, 3000 );   

}


void displayTemperature(int unit) {
    display.clear();  // Clear display before new content
    
    // Line 1: "Temperature:" in 16pt font
    display.setTextAlignment(TEXT_ALIGN_LEFT);


    // Line 2: Temperature value in 24pt font
    display.setFont(ArialMT_Plain_24);
    
    // Format temperature with correct unit symbol
    String tempStringC = String(tempC, 1) + "°C"; // 1 decimal place
    String tempStringF = String(tempF, 1)+ "°F"; // 1 decimal place
    String tempStringHumidity = String(humidity)+ "% RH";   
    String tempString; 
    switch(unit) {
        case 1:  
          tempString =tempStringC; 
          display.setFont(ArialMT_Plain_16);
          display.drawString(0, 0, "Temperature:");        
          display.setFont(ArialMT_Plain_24);
          display.drawString(0, 15, tempString);  
          break;  // Celsius
        case 2:  tempString =tempStringF; 
          display.setFont(ArialMT_Plain_16);
          display.drawString(0, 0, "Temperature:");              
          display.setFont(ArialMT_Plain_24);
          display.drawString(0, 15, tempString);  
          break;  // Fahrenheit
        case 3:  tempString =tempStringC; 
          display.setFont(ArialMT_Plain_16);
          display.drawString(0, 0, "Temperature:");              
          display.setFont(ArialMT_Plain_24);        
          display.drawString(0, 15, tempString);  
          display.setFont(ArialMT_Plain_16);
          display.drawString(0, 40, "Humidity:");
          display.drawString(70, 40, tempStringHumidity);       
          break;  // Celsius    
        case 4:  tempString =tempStringF; 
          display.setFont(ArialMT_Plain_16);
          display.drawString(0, 0, "Temperature:");              
          display.setFont(ArialMT_Plain_24);        
          display.drawString(0, 15, tempString);  
          display.setFont(ArialMT_Plain_16);
          display.drawString(0, 40, "Humidity:");
          display.drawString(70, 40, tempStringHumidity );       
          break;  // Celsius       
        case 5: 
          display.setFont(ArialMT_Plain_16);
          display.drawString(0, 0, "Humidity:");
          display.setFont(ArialMT_Plain_24); 
          display.drawString(0, 20, tempStringHumidity);         
          break;  // Celsius                     
        default: tempString =tempStringC + "°C"; break;;  // default
    }
    

    display.display();  // Update OLED
}

void readSensor()
{
  tempC = dht.readTemperature();
  humidity = dht.readHumidity(); 
  tempF = dht.convertCtoF(tempC);
}


void VextON(void)
{
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, LOW);
}

void VextOFF(void) //Vext default OFF
{
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, HIGH);
}

void sendData()
{
  

    String tempStringC = String(tempC, 1) + " °C"; // 1 decimal place
    String tempStringF = String(tempF, 1)+ " °F"; // 1 decimal place
    String tempStringHumidity = String(humidity)+ " % RH";   
    String txData; 
    //1=C
    //2=F
    //3=C, Humidity
    //4=F, Humidity
    //5=Humidity only
        switch(dataType) {
          case 1: 
           txData = labelTemp + " " + tempStringC;
            break; 
          case 2: 
           txData =  labelTemp + " " + tempStringF;
            break;
          case 3: 
           txData = labelHumidity + " " + tempStringHumidity;
            break;             
          default:
           txData = labelTemp + " " + tempStringC;
            break;

        }
  uint8_t data[32];       
  memset(data, 0, sizeof(data));  // Zero-padding
  strncpy((char*)data, txData.c_str(), sizeof(data) - 1); // Copy string safely

  encryptAES(data, userKey);  // Encrypt before sending  
  if(lora_idle == true)
    {
      delay(1000);
      Radio.Send(data,  sizeof(data));
      Serial.print("Sending: ");
      Serial.println((char *)data);
      lora_idle = false;
    }
    Radio.IrqProcess( );  
}



void loop() {
  readSensor();//read the data

  // clear the display
  display.clear();

  displayTemperature(dataType); // 
	sendData();
  delay(100);

}


void OnTxDone( void )
{
	Serial.println("TX done......");
	lora_idle = true;
}

void OnTxTimeout( void )
{
    Radio.Sleep( );
    Serial.println("TX Timeout......");
    lora_idle = true;
}


/**
 * Converts a user-provided plaintext key into a fixed-length 16-byte (128-bit)
 * or 32-byte (256-bit) key.
 */
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize) {
    memset(processedKey, 0, keySize); // Fill with zeros
    size_t len = strlen(userKey);
    if (len > keySize) len = keySize; // Truncate if too long
    memcpy(processedKey, userKey, len); // Copy valid key part
}

/**
 * Encrypts a 16-byte (one block) message using AES-128.
 */
void encryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16]; // 128-bit key
    processKey(key, processedKey, 16);

    mbedtls_aes_init(&aes);
    mbedtls_aes_setkey_enc(&aes, processedKey, 128);
    mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_ENCRYPT, data, data);
    mbedtls_aes_free(&aes);
}

/**
 * Decrypts a 16-byte (one block) message using AES-128.
 */
void decryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16]; // 128-bit key
    processKey(key, processedKey, 16);

    mbedtls_aes_init(&aes);
    mbedtls_aes_setkey_dec(&aes, processedKey, 128);
    mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_DECRYPT, data, data);
    mbedtls_aes_free(&aes);
}

/*
Written on April 01, 2025
written by Ahmad Shamshiri for www.Robojax.com
this sktech receives the secure temperature or humidity from WiFi LoRa 32 and decrypts it
and displays it on the OLED. There is action feature to triggerd if the temperature is below triggerdValue
Watch full video explaination https://youtu.be/WkyQMXkQhE8
Resources page: https://robojax.com/tutorial_view.php?id=387
*/
#include <Arduino.h>
// Alert configuration
const String triggerdText = "Too High"; // Correct String type
const float triggerdValue = 90.0f; // exclusive (this value is not included)
const int triggerdYpos = 45;
const bool triggerdType = true;//true is > (greter than triggerdValue) and false is < (less  than triggerdValue)
const int triggerdOutputPin = 7;//GPIO07 goes HIGH when triggered
const bool triggerdBlink4Me= true;//should blink or not

#include "mbedtls/aes.h"
#include <cstring>  // For memset, memcpy
mbedtls_aes_context aes;
const char *userKey = "hyhT676#h~_876s"; //Security key

#define MIN_RSSI -120  // Worst possible signal
#define MAX_RSSI -50   // Best possible signal


// For a connection via I2C using the Arduino Wire include:
#include <Wire.h>               
#include "HT_SSD1306Wire.h"

static SSD1306Wire  display(0x3c, 500000, SDA_OLED, SCL_OLED, GEOMETRY_128_64, RST_OLED); // addr , freq , i2c group , resolution , rst



#include "LoRaWan_APP.h"
#include "Arduino.h"


#define RF_FREQUENCY                                915000000 // Hz

#define TX_OUTPUT_POWER                             14        // dBm

#define LORA_BANDWIDTH                              0         // [0: 125 kHz,
                                                              //  1: 250 kHz,
                                                              //  2: 500 kHz,
                                                              //  3: Reserved]
#define LORA_SPREADING_FACTOR                       7         // [SF7..SF12]
#define LORA_CODINGRATE                             1         // [1: 4/5,
                                                              //  2: 4/6,
                                                              //  3: 4/7,
                                                              //  4: 4/8]
#define LORA_PREAMBLE_LENGTH                        8         // Same for Tx and Rx
#define LORA_SYMBOL_TIMEOUT                         0         // Symbols
#define LORA_FIX_LENGTH_PAYLOAD_ON                  false
#define LORA_IQ_INVERSION_ON                        false


#define RX_TIMEOUT_VALUE                            1000
#define BUFFER_SIZE                                 30 // Define the payload size here

char txpacket[BUFFER_SIZE];
char rxpacket[BUFFER_SIZE];

static RadioEvents_t RadioEvents;

int16_t txNumber;

int16_t rssi,rxSize;

bool lora_idle = true;
unsigned long lastRxTime = 0;
const unsigned long SIGNAL_TIMEOUT = 5000; // 5 seconds

void decryptAES(uint8_t *data, const char *key);
void encryptAES(uint8_t *data, const char *key);
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize);

void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.println();
  VextON();
  delay(100);

  // Initialising the UI will init the display too.
  display.init();

  display.setFont(ArialMT_Plain_10);
  pinMode(triggerdOutputPin, OUTPUT);
  //LoRa stuff blow this line
     Mcu.begin(HELTEC_BOARD,SLOW_CLK_TPYE);
    
    txNumber=0;
    rssi=0;
  
    RadioEvents.RxDone = OnRxDone;
    Radio.Init( &RadioEvents );
    Radio.SetChannel( RF_FREQUENCY );
    Radio.SetRxConfig( MODEM_LORA, LORA_BANDWIDTH, LORA_SPREADING_FACTOR,
                               LORA_CODINGRATE, 0, LORA_PREAMBLE_LENGTH,
                               LORA_SYMBOL_TIMEOUT, LORA_FIX_LENGTH_PAYLOAD_ON,
                               0, true, 0, 0, LORA_IQ_INVERSION_ON, true );
}


void displayTemperature(String data1, String data2) {

    display.clear();  // Clear display before new content
    
    // Line 1: "Temperature:" in 16pt font
    display.setTextAlignment(TEXT_ALIGN_LEFT);
    display.setFont(ArialMT_Plain_16);
    display.drawString(0, 0, data1);

    // Line 2: Temperature value in 24pt font
    display.setFont(ArialMT_Plain_24);
    display.drawString(0, 20, data2);  // 
    displaySignalStrength(rssi);
   // display.display();  // Update OLED

    
}

void displayLine(String data, int y) {
    // Line 1: "Temperature:" in 16pt font
    display.setTextAlignment(TEXT_ALIGN_LEFT);
    display.setFont(ArialMT_Plain_10);

    if (triggerdBlink4Me) {
        // Blink effect: Display text, wait, clear text, wait, then return
        display.drawString(0, y, data);
        display.display();
        delay(500);  // Keep text visible for 500ms

        display.clear();  // Clear the screen
        display.display();
        delay(500);  // Keep screen blank for 500ms
    } 
    else {
        // Normal display without blinking
        display.drawString(0, y, data);
        display.display();
    }
}


void VextON(void)
{
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, LOW);
}

void VextOFF(void) //Vext default OFF
{
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, HIGH);
}



void loop() {
  RaIrqProcessdio( );
  if(lora_idle)
  {
    lora_idle = false;
    Serial.println("into RX mode");
    Radio.Rx(0);
  }
  noSignalCheck();

  delay(100);

}

void displaySignalStrength(int16_t rssi) {
    // Convert RSSI to percentage (0-100%)
    int percent = map(constrain(rssi, MIN_RSSI, MAX_RSSI), MIN_RSSI, MAX_RSSI, 0, 100);
    
    // Display at bottom right corner
    display.setTextAlignment(TEXT_ALIGN_RIGHT);
    display.setFont(ArialMT_Plain_16);
    
    // Create signal strength indicator
    String strength = String(percent) + "% [";
    for (int i = 0; i < 5; i++) {
        strength += (percent > (i * 20)) ? "|" : " ";
    }
    strength += "]";
    
    display.drawString(128, 45, strength); // Position at bottom-right
}

void noSignalCheck()
{
    // Automatic "No Signal" after timeout
    if (millis() - lastRxTime > SIGNAL_TIMEOUT) {
        display.clear();
        display.setTextAlignment(TEXT_ALIGN_CENTER);
        display.setFont(ArialMT_Plain_16);        
        display.drawString(64, 20, "No Signal");
        display.display();
    }
}

/**
 * Triggers an action based on a threshold comparison.
 *
 * @param type           - If true, triggers when floatValue **exceeds** triggerdValue.
 *                         If false, triggers when floatValue **falls below** triggerdValue.
 * @param floatValue     - The current measured value to compare.
 * @param triggerdValue  - The threshold value that determines the trigger condition.
 */
void triggerAction(float floatValue)
{
  if(triggerdType)
  {
    if (floatValue > triggerdValue) {
        displayLine(triggerdText, triggerdYpos);
        Serial.println(triggerdText);
        digitalWrite(triggerdOutputPin, HIGH);//turns triggerdOutputPin to HIGH
    }else{
        digitalWrite(triggerdOutputPin, LOW);
    }
  }else{
    if (floatValue < triggerdValue) {
        displayLine(triggerdText, triggerdYpos);
        Serial.println(triggerdText);
        digitalWrite(triggerdOutputPin, HIGH);//turns triggerdOutputPin to HIGH
    } else{
        digitalWrite(triggerdOutputPin, LOW);//turns triggerdOutputPin to LOW
    }   
  }
}
void OnRxDone( uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr )
{
    lastRxTime = millis(); // Reset timer on new data
    rssi=rssi;
    rxSize=size;
    memcpy(rxpacket, payload, size );

    rxpacket[size]='\0';
    Radio.Sleep( );
    Serial.printf("\r\nreceived packet \"%s\" with rssi %d , length %d\r\n",rxpacket,rssi,rxSize);
    // Serial.println("Encrypted Data (Hex):");
    // for (int i = 0; i < 16; i++) {
    //     Serial.printf("%02X ", rxpacket[i]);
    // }
    // Serial.println();
   decryptAES((uint8_t *)rxpacket, userKey);

    // Split the received packet into parts
    String receivedStr = String((char*)rxpacket);
    int firstSpacePos = receivedStr.indexOf(' ');
    if (firstSpacePos != -1) {
        // First part (before first space)
        String part1 = receivedStr.substring(0, firstSpacePos);  // "Temperature"
        
        // Find second space (after the number)
        int secondSpacePos = receivedStr.indexOf(' ', firstSpacePos + 1);
        
        if (secondSpacePos != -1) {
            // Second part (numeric value)
            String part2 = receivedStr.substring(firstSpacePos + 1, secondSpacePos); // "34.5"
            float floatValue = part2.toFloat();  // Convert to float 34.5
            
            // Third part (unit)
            String part3 = receivedStr.substring(secondSpacePos + 1); // "°C"
            
            displayTemperature(part1, part2+part3);
            display.display();
            Serial.print("part1: " + part1);
            Serial.print(" part2: " + part2);
            Serial.println(" part3: " + part3);
            Serial.println("floatValue " + String(floatValue));          
        
        //to trigger an action. 
        triggerAction(floatValue);

        } else {
            Serial.println("No second space found for unit");
        }
    }else {
        Serial.println("No space found in packet - can't split");
    }     


    lora_idle = true;
}

/**
 * Converts a user-provided plaintext key into a fixed-length 16-byte (128-bit)
 * or 32-byte (256-bit) key.
 */
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize) {
    memset(processedKey, 0, keySize); // Fill with zeros
    size_t len = strlen(userKey);
    if (len > keySize) len = keySize; // Truncate if too long
    memcpy(processedKey, userKey, len); // Copy valid key part
}

/**
 * Encrypts a 16-byte (one block) message using AES-128.
 */
void encryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16]; // 128-bit key
    processKey(key, processedKey, 16);

    mbedtls_aes_init(&aes);
    mbedtls_aes_setkey_enc(&aes, processedKey, 128);
    mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_ENCRYPT, data, data);
    mbedtls_aes_free(&aes);
}

/**
 * Decrypts a 16-byte (one block) message using AES-128.
 */
void decryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16]; // 128-bit key
    processKey(key, processedKey, 16);

    mbedtls_aes_init(&aes);
    mbedtls_aes_setkey_dec(&aes, processedKey, 128);
    mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_DECRYPT, data, data);
    mbedtls_aes_free(&aes);
}