Projet ESP32: Boti esengeli ya LoRa ya libela mpe ya libateli na nzela ya mosika. Heltec WiFi LoRa 32 na N33

Leçon ci est une partie de: Maloba ya ebandeli na WiFi LoRa

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Bokoli Bosi

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Projet ESP32: Boti esengeli ya LoRa ya libela mpe ya libateli na nzela ya mosika. Heltec WiFi LoRa 32 na N33

Bongisa Message ya LoRa ya Libanga, Longola na Grille ya Elektricité na Clavier ya Personnalisé

Na mokili oyo etiaka motuya na connexion ya libela, okosala nini soki Wi-Fi esili, courant esili, mpe service ya téléphone esili? Projet oyo ezali koyanola na problème yango na kosala appareil ya communication oyo ezali na bomoi ya nsima, oyo esalaka ete okoka kotinda mpe kozwa ba messages ya texte ya sécurisé mpe ya privé na mosika ya kilomètres 13 (21km) to koleka.

Appareil oyo ezali outil ya pratique mpo na préparation ya likambo ya libanga, ba aventures ya libanda lokola kotambola na ngomba, to mpo na moto nyonso oyo azali na intérêt ya kotonga réseau ya communication ya solide mpe ya privé oyo ye nde azali kokamba. Na kosalela module ya puissant Heltec WiFi LoRa 32 V3 oyo ezali na kati ya boîte ya solide Meshnology N33 na batterie ya 3000mAh oyo ewumelaka mingi, projet oyo esalemi mpo na kosalela na bomoi ya solo. Caractéristique oyo ezali penza unique ezali clavier na yango—encodeur rotatif ya pete oyo epesaka ndenge ya komprenama mpe ya semba mpo na kokoma ba messages na esika nyonso, na ntango nyonso.

Ndenge Ezali Kosala: Magie ya LoRa mpe Encodeur Rotatif

Projet oyo esangisi ba concepts misato ya minene mpo na kosala messagerie oyo esalaka:

Radio LoRa: LoRa (Long Range) ezali technologie ya radio oyo epesaka possibilité ya communication na ba distances ya minene na puissance moke. Na ndenge ya kokesana na Wi-Fi to téléphone, esalaka na ba fréquences radio oyo ezali na licence te, elingi koloba ete ezali na ba SIM cards te to frais ya sanza te. Appareil na biso esalaka lokola transceiver ya mobimba, elingi koloba ete ekoki kotinda mpe kozwa ba messages. Ntango ezali kosala eloko te, ezali koyoka mpo na ba paquets oyo ezali koya. Na nsima ya kotinda to kozwa message, ezali kolalisa radio mwa mwa mpo na kobatela puissance liboso ya kozonga na ndenge ya koyoka.
Clavier ya Encodeur Rotatif: Na esika ya clavier ya monene to oyo esalelaka mingi courant, tosalelaka encodeur rotatif ya pete mpo na kokoma texte. Kozongola bouton ezali koleka na caractères nyonso (A-Z, a-z, ba nombres, mpe ba symboles). Interface yango ezali mbangu mpe ezali koyanola mbala moko, oyo epesaka ete okoka kosala ba messages na mpasi te. Bouton ya push oyo ezali na kati ya encodeur ezali na fonctions misato:
- Press ya mokuse (Click): Ebakisaka caractère oyo oponi na message na yo.
- Press ya molai (Hold): Ebakisaka espace, lokola bouton ya espace.
- Double-Click: Esalaka lokola backspace mpo na kolongola caractère ya suka.
Transceiver & Logique ya Affichage: Appareil oyo ezali na ba modes mibale ya minene: "Compose" mpe "Read". Okomaka message na yo na mode Compose. Ntango message ya sika eyi, notification emonanaka na écran (>> NEW MSG <<). Na yango, okoki kopresser Bouton ya Utilisateur oyo ezali na board (na board ya Heltec) mpo na kobongola na mode Read mpe komona message. Press mosusu ekomisaka yo na mode Compose mpo na kokoma eyano na yo. Ba messages nyonso ezali na sécurité na kosalela AES encryption, oyo esungaka ete ba conversations na yo ezala ya privé.

Ba Composants mpe Liste ya Ba Parties

Mpo na kosala projet oyo, okobanga ba composants oyo elandi. Lokola emonani na vidéo, kosomba na ba liens affiliés ezali ndenge ya malamu ya kosunga ba créateurs.

Module Heltec WiFi LoRa 32 V3
Boîte Meshtastic N33 na Batterie ya 3000mAh
Antenne LoRa ya 915MHz to ya région oyo ekoki
Module ya Encodeur Rotatif (5-pin na VCC, GND, CLK, DT, SW)
Optionnel (mpo na ba alertes ya son):
- Buzzer Actif ya 5V
- Transistor NPN 2N2222
- Résistance ya 1kΩ
Ba Pin Headers mpe Ba Fils ya Jumper
Fer ya kosolda mpe ba accessoires

Kobongisa Arduino IDE na Yo

Liboso ya kotinda code, okobanga kobongisa Arduino IDE na ba boards mpe ba bibliothèques ya semba. Processus oyo ezali na détail na vidéo na ntango ya 05:38.

Etape 1: Tia ba Boards ya ESP32

Soki osili te, okobanga kobakisa support mpo na ba microcontrôleurs ESP32.

Fungola Arduino IDE, kende na File > Preferences.
Na esika ya "Additional boards manager URLs", bakisa URL oyo elandi: https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
Kende na Tools > Board > Boards Manager....
Luka esp32 mpe tia paquet oyo esalemi na Espressif Systems.

Etape 2: Bakisa Support ya Board ya Heltec ESP32

Na File > Preferences, bakisa URL ya JSON ya Heltec na ligne ya sika na esika ya "Additional boards manager URLs" (vidéo emonisi ndenge ya kosala yango na 06:27): https://github.com/Heltec-Aaron-Lee/WiFi_Kit_series/releases/download/0.0.7/package_heltec_esp32_index.json
Zonga na Tools > Board > Boards Manager....
Luka Heltec ESP32 mpe tia paquet yango.

Etape 3: Tia Ba Bibliothèques ya Esengeli na Library Manager

Na kosalela Arduino Library Manager (Sketch > Include Library > Manage Libraries...), luka mpe tia ba bibliothèques oyo elandi:

Ai Esp32 Rotary Encoder: Bibliothèque ya spécifique oyo tosalelaki mpo na clavier na biso oyo eyanolaka mbala moko.
Heltec ESP32 Dev-Boards: Bibliothèque officielle mpo na matériel ya Heltec.
Adafruit GFX Library: Dépendance mpo na écran OLED.

Etape 4: Tia Bibliothèque ya Helper ya Robojax na .ZIP

Lokola elobami na vidéo na 18:53, bibliothèque ya helper ya personnalisé esalelami mpo na projet oyo. Okobanga kotia yango na fichier .zip.

Kokisa téléchargement ya bibliothèque .zip ya "Robojax HealthTech Lora 32" na lien oyo epesami na page ya ba ressources.
Na Arduino IDE, klik na Sketch > Include Library > Add .ZIP Library....
Kende na esika oyo obombaki fichier .zip oyo okitisaki, pona yango, mpe klik na "Open".
Bibliothèque yango ekotiama mpe ekosala mpo na kosalela.

Sima na osili biloko nyonso, sɔtɔ ete opɔni carte ya mibale oyo ebongi na menu: Tools > Board > Heltec ESP32 Arduino > Heltec WiFi LoRa 32 V3.

Kokangisa Baparti ya Elektroniki

Okosengela kosolda ba pin ya motó na carte na yo ya Heltec mpo na kokangisa rotary encoder. Lokola emonani na vidéo (11:25), esengeli kosala plan ya malamu mpo na komeka ete ba pin ezala na esika oyo bato bakoki kozwa yango tango carte ezali na kati ya boîte na yango.

Helte_Wifi_LoRA_Rotary_Encoder

Diagram 1: Core Messenger (Rotary Encoder Séulment)

Kokangisa ba pin 5 oyo ewuti na module ya rotary encoder na carte ya Heltec lokola oyo elandi:

GND na encoder → GND na carte ya Heltec
VCC na encoder → 3.3V na carte ya Heltec
SW (Switch) → GPIO 4
DT (Data/Pin B) → GPIO 6
CLK (Clock/Pin A) → GPIO 5

Helte_Wifi_LoRA_Rotary_Encoder with buzzer

Diagram 2: Kobakisa Lolenge ya Koyoka (Circuit ya Buzzer)

Mpo na koyoka mongongo ya beep tango sika ya sika eyei, okoki kobakisa circuit ya transistor ya pete. Esengeli mpo ete ba pin ya ESP32 bakoki te kopesa courant ya koleka mpo na kopelisa buzzer na ndenge ya mibale.

Kokangisa GPIO 40 na carte ya Heltec na esika moko ya résistance ya 1kΩ.
Kokangisa esika mosusu ya résistance na pin ya Base ya transistor 2N2222.
Kokangisa pin ya Emitter ya transistor na GND.
Kokangisa lokolo ya positif (+) ya buzzer ya 5V na pin ya 3.3V na carte ya Heltec.
Kokangisa lokolo ya négatif (-) ya buzzer na pin ya Collector ya transistor.

Koyeba mpe Kobongola Code

Code oyo epesami esili mpo na kotombola, kasi ezali na ba réglages ya ntina mingi oyo esengeli oyeba mpo na kobongola projet. Ba définitions oyo ezali na likoló ya code.


// Définitions mpo na ba connexions ya ba pin ya physique
#define ROTARY_ENCODER_A_PIN 5 //pin A ya rotary encoder
#define ROTARY_ENCODER_B_PIN 6 //pin B ya rotary encoder
#define ROTARY_ENCODER_BUTTON_PIN 4 //pin ya switch ya rotary encoder
#define BUZZER_PIN 40 //pin ya buzzer to relais oyo esengeli kopelisa
const bool DEBUG = false;

// Définitions mpo na ba réglages ya LoRa mpe ya sécurité
#define RF_FREQUENCY 915432000 //fréquence ya fonctionnement ya LoRa
#define TX_OUTPUT_POWER 2 //puissance ya sortie esengeli kozala entre 2 na 21 na dBm. 
const char *userKey = "xxxBg^Tr%43232";//clé ya sécurité mpo na communication ya ba personnes moko

ROTARY_ENCODER_...: Ba pin oyo balakisi esika okangisaki rotary encoder na yo. Sɔtɔ ete ba nombres oyo bakokani na ba connexions na yo na ba diagram oyo ezali na likoló.
BUZZER_PIN: Oyo elakisi pin nini ekopelisa circuit ya buzzer.
RF_FREQUENCY: Oyo ezali fréquence ya fonctionnement ya LoRa na Hertz. Valeur 915432000 (915 MHz) ezali standard mpo na Amérique ya Nor. Esengeli obongola valeur oyo kolanda région na yo (mpe., 868MHz mpo na Europe, 433MHz mpo na Asie). Ba appareils nyonso oyo balingi kosolola esengeli kosalela fréquence moko.
TX_OUTPUT_POWER: Oyo ezali puissance ya transmission na dBm. Ekoki kozala na 2 kino 20. Nombre ya moke lokola 2 ezali malamu mpo na test ya mosika moke mpe ebikisaka batterie mingi. Mpo na mosika ya koleka, okoki kobakisa valeur oyo, kasi yeba ete puissance ya likoló ekolimwisa batterie noki mingi.
userKey: Oyo ezali clé ya cryptage ya ba personnes moko. Ekoki kozala na ba combinaisons nyonso ya ba caractères. Ba appareils nyonso esengeli kozala na clé moko ya mbala moko mpo na kofungola ba messages ya bato mosusu. Bongola oyo na mot de passe na yo ya sika mpe ya securité.

Kozwa Code

Code ya Arduino ya mobimba mpe ya suka mpo na projet oyo, lokola elobelami na vidéo, ezali mpo na téléchargement na page oyo.

Ba Chapitres ya Vidéo

00:00 - Introduction
00:56 - Résumé ya Projet
01:29 - Baparti ya Komponen
05:25 - Kofungola mpe Kosangisa Hardware
11:19 - Kobongola Boîte mpo na Ba Fili ya Libanda
15:06 - Guide ya Kokangisa
15:38 - Arduino IDE mpe Bibliothèque Setup
20:21 - Ba Réglages ya Code Elobami
21:38 - Ndenge ya Kosalela Rotary Encoder mpo na Kosolola
24:26 - Test ya Mosika na Ntango ya Sika

Please view this page in English if the code is not visible. We’re sorry for the inconvenience.

785-Secure, Long-Range LoRa Chat Device Heltec WiFi LoRa 32

Langue: C++

/*
ESP32 Project: Build a Secure, Long-Range LoRa Chat Device Heltec WiFi LoRa 32

File: Heltec_ESP32_LoRa_V3_chat_TX_RX.ino
written on 29 Jun, 2025 by Ahmad Shamshiri www.Roboajx.com
 * Please watch the tutorial video at: https://youtu.be/IsOSvrF60J4
 * Resources page for this video: https://robojax.com/RJT642
 
 * =====================================================================
 * ARDUINO CODE DESCRIPTION: SECURE LoRa  Keyboard Transceiver (chat system)
 * =====================================================================
 * 
 * HARDWARE COMPONENTS:
 * -------------------
 *  - Main Controller: Heltec WiFi LoRa 32 V3
 *  - Enclosure: Meshnology N33 case with 3000mAh battery
 *  - Input: Rotary encoder with push-button
 *  - Feedback: Built-in OLED display
 * 
 * SYSTEM FUNCTIONALITY:
 * -------------------
  NEW CONTROLS:
  - Rotate Knob:         Select character.
  - Short Press (Click): Add selected character.
  - Long Press (Hold):   Insert a space (like a spacebar).
  - Double Click:        Backspace.
 * 
 * [2] SECURE WIRELESS TRANSMISSION:
 *     - All message  encrypted before LoRa transmission
 *     - Home position command transmitted as special secure packet
 *     - Uses 433MHz/915MHZ LoRa band for reliable communication
 * 
 * [3] POWER MANAGEMENT:
 *     - Optimized for battery operation (3000mAh)
 *     - Low-power modes between transmissions
 * 
 * FOR COMPLETE SETUP INSTRUCTIONS:
 * Please watch the tutorial video at: https://youtu.be/IsOSvrF60J4
 * Resources page for this video: https://robojax.com/RJT642
 * =====================================================================


 * DISCLAIMER:
 * This code is provided "AS IS" without warranty of any kind. The author 
 * shall not be held liable for any damages arising from the use of this code.
 * 
 * LICENSE:
 * This work is licensed under the GNU General Public License v3.0 
 * Permissions beyond the scope of this license may be available at Robojax.com
 * 
 * SHARING TERMS:
 * You are free to share, copy and modify this code for non-commercial purposes
 * PROVIDED you:
 * 1. Keep this entire comment block intact with the original code
 * 2. Include the original Robojax.com link
 * 3. Keep the YouTube tutorial link (if applicable)
 * 4. Clearly indicate any modifications made
 * 

 * 
 * ********************************************************************
 */
// Core Heltec and display libraries
#include <Wire.h>
#include "HT_SSD1306Wire.h"
#include "WiFi.h"

// LoRa and security libraries
#include "LoRaWan_APP.h"
#include "mbedtls/aes.h"
#include <cstring>

// The user-approved Rotary Encoder library
#include "AiEsp32RotaryEncoder.h"

// --- PIN DEFINITIONS & CONFIGURATION ---
static SSD1306Wire  display(0x3c, 500000, SDA_OLED, SCL_OLED, GEOMETRY_128_64, RST_OLED);

#define ROTARY_ENCODER_A_PIN 5 //pin A of rotary encoder
#define ROTARY_ENCODER_B_PIN 6 //pin B of rotary encoder
#define ROTARY_ENCODER_BUTTON_PIN 4 //switch pin of rotary encoder

#define RF_FREQUENCY 915432000 //operating frequey of LoRa
#define TX_OUTPUT_POWER 20 //output power should be between 2 to 21 in dBm. 
const char *userKey = "wahJ8uy$gt~_3r";//secureity key for private communication

#define ROTARY_ENCODER_VCC_PIN -1
#define ROTARY_ENCODER_STEPS 4

// --- LORA PARAMETERS ---
#define LORA_BANDWIDTH 0
#define LORA_SPREADING_FACTOR 7
#define LORA_CODINGRATE 1
#define LORA_PREAMBLE_LENGTH 8
#define LORA_SYMBOL_TIMEOUT 0
#define LORA_FIX_LENGTH_PAYLOAD_ON false
#define LORA_IQ_INVERSION_ON false
#define BUFFER_SIZE 256

#define USER_BUTTON_PIN 0
// --- GLOBAL VARIABLES & STATE ---
enum AppState { COMPOSING, READING };
AppState currentState = COMPOSING;
String messageToCompose = "";
String lastReceivedMessage = "No messages yet.";
bool hasUnreadMessage = false;
volatile bool newPacketAvailable = false;
char rxpacket[BUFFER_SIZE];
AiEsp32RotaryEncoder rotaryEncoder = AiEsp32RotaryEncoder(ROTARY_ENCODER_A_PIN, ROTARY_ENCODER_B_PIN, ROTARY_ENCODER_BUTTON_PIN, ROTARY_ENCODER_VCC_PIN, ROTARY_ENCODER_STEPS);
const char* charset = " ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.,!?>";
char selectedChar;
static RadioEvents_t RadioEvents;
bool lora_idle = true;

mbedtls_aes_context aes;
unsigned long shortPressAfterMiliseconds = 50;
unsigned long longPressAfterMiliseconds = 1000;
unsigned long doubleClickTimeout = 400;
static unsigned long buttonDownTime = 0;
static unsigned long buttonUpTime = 0;
static bool buttonWasDown = false;
static bool doubleClickWaiting = false;

// --- FUNCTION PROTOTYPES ---
void OnTxDone(void);
void OnTxTimeout(void);
void OnRxDone(uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr);
void encryptAES(uint8_t *data, const char *key);
void decryptAES(uint8_t *data, const char *key);
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize);
void updateDisplay();
void sendData();
void VextON(void);
void processButton();

// --- INTERRUPT SERVICE ROUTINES ---
void IRAM_ATTR readEncoderISR() {
  rotaryEncoder.readEncoder_ISR();
}

// --- BUTTON HANDLER ACTIONS ---
void on_button_short_click() {
  if (currentState != COMPOSING) return;
  if (selectedChar == '>') {
      sendData();
  } else {
    messageToCompose += selectedChar;
  }
  updateDisplay();
}
void on_button_long_click() {
  if (currentState != COMPOSING) return;
  messageToCompose += " ";
  updateDisplay();
}
void on_button_double_click() {
  if (currentState != COMPOSING) return;
  if (messageToCompose.length() > 0) {
    messageToCompose.remove(messageToCompose.length() - 1);
  }
  updateDisplay();
}

// --- SETUP ---
void setup() {
  Serial.begin(115200);
  Serial.println("LoRa Keyboard Transceiver - Definitive Version");

  VextON();
  delay(100);
  Mcu.begin(HELTEC_BOARD,SLOW_CLK_TPYE);
  WiFi.mode(WIFI_OFF);
  btStop();

  display.init();
  display.setFont(ArialMT_Plain_10);

  rotaryEncoder.begin();
  rotaryEncoder.setup(readEncoderISR);
  rotaryEncoder.setBoundaries(0, strlen(charset) - 1, true);
  rotaryEncoder.disableAcceleration();

  pinMode(USER_BUTTON_PIN, INPUT_PULLUP);

  RadioEvents.TxDone = OnTxDone;
  RadioEvents.TxTimeout = OnTxTimeout;
  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);
  
  updateDisplay();
}

// --- MAIN LOOP ---
void loop() {
  if(lora_idle) {
    lora_idle = false;
    Serial.println("Entering RX mode...");
    Radio.Rx(0);
  }
  Radio.IrqProcess(); 

  if (newPacketAvailable) {
    newPacketAvailable = false;
    hasUnreadMessage = true;
    lastReceivedMessage = String(rxpacket);
    Serial.print("Received Decrypted Message: ");
    Serial.println(lastReceivedMessage);
    updateDisplay();
  }
  
  if (currentState == COMPOSING) {
    if (rotaryEncoder.encoderChanged()) {
      updateDisplay();
    }
    processButton();
  }
  
  if (digitalRead(USER_BUTTON_PIN) == LOW) {
    delay(50);
    if (digitalRead(USER_BUTTON_PIN) == LOW) {
      if (currentState == COMPOSING) {
        if (lastReceivedMessage != "No messages yet.") {
          currentState = READING;
          hasUnreadMessage = false;
          updateDisplay();
        }
      } else {
        currentState = COMPOSING;
        updateDisplay();
      }
      while (digitalRead(USER_BUTTON_PIN) == LOW);
    }
  }
  
  delay(10);
}

// --- LORA EVENT HANDLERS & HELPERS ---
void OnTxDone(void) {
  Serial.println("TX done.");
  Radio.Sleep();
  lora_idle = true;
}
void OnTxTimeout(void) {
  Serial.println("TX Timeout.");
  Radio.Sleep();
  lora_idle = true;
}
void OnRxDone(uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr) {
    Radio.Sleep();
    memset(rxpacket, 0, sizeof(rxpacket));
    memcpy(rxpacket, payload, size > BUFFER_SIZE ? BUFFER_SIZE : size);
    decryptAES((uint8_t*)rxpacket, userKey);
    newPacketAvailable = true;
    lora_idle = true;
}

void sendData() {
  if (messageToCompose.length() > 0) {
    lora_idle = false; 
    
    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);

    uint8_t data[BUFFER_SIZE];
    memset(data, 0, BUFFER_SIZE);
    strncpy((char*)data, messageToCompose.c_str(), BUFFER_SIZE - 1);
    
    encryptAES(data, userKey);

    Serial.print("Sending message: ");
    Serial.println(messageToCompose);

    Radio.Send(data, 16);
    
    messageToCompose = "";
  }
}

// --- DISPLAY & BUTTON LOGIC ---
void updateDisplay() {
  display.clear();
  display.setTextAlignment(TEXT_ALIGN_LEFT);

  if (currentState == COMPOSING) {
    selectedChar = charset[rotaryEncoder.readEncoder()];
    display.setFont(ArialMT_Plain_10);
    
    // --- THIS IS THE FIX for the notification ---
    String msgLabel;
    if (hasUnreadMessage) {
        msgLabel = ">> NEW MSG <<"; // Make the notification very obvious
    } else {
        msgLabel = "Msg:";
    }
    display.drawStringMaxWidth(0, 0, 128, msgLabel + " " + messageToCompose);

    display.setFont(ArialMT_Plain_16);
    int16_t labelWidth = display.getStringWidth("Select: ");
    display.drawString(0, 35, "Select: ");
    display.setFont(ArialMT_Plain_24);
    display.drawString(labelWidth, 32, String(selectedChar));
  } else { // currentState == READING
    display.setFont(ArialMT_Plain_16);
    display.drawString(0, 0, "Received:");
    display.setFont(ArialMT_Plain_10);
    display.drawStringMaxWidth(0, 18, 128, lastReceivedMessage);
  }
  
  display.display();
}

void processButton() {
    if (doubleClickWaiting && (millis() - buttonUpTime > doubleClickTimeout)) {
        doubleClickWaiting = false;
        on_button_short_click();
    }
    bool isButtonDown = rotaryEncoder.isEncoderButtonDown();
    if (isButtonDown && !buttonWasDown) {
        buttonDownTime = millis();
        buttonWasDown = true;
    } 
    else if (!isButtonDown && buttonWasDown) {
        unsigned long pressDuration = millis() - buttonDownTime;
        if (pressDuration >= longPressAfterMiliseconds) {
            on_button_long_click();
            doubleClickWaiting = false;
        } 
        else if (pressDuration >= shortPressAfterMiliseconds) {
            if (doubleClickWaiting) {
                on_button_double_click();
                doubleClickWaiting = false;
            } else {
                doubleClickWaiting = true;
                buttonUpTime = millis();
            }
        }
        buttonWasDown = false;
    }
}

// --- UTILITIES ---
void VextON(void) {
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, LOW);
}
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize) {
    memset(processedKey, 0, keySize);
    size_t len = strlen(userKey);
    if (len > keySize) len = keySize;
    memcpy(processedKey, userKey, len);
}
void encryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16];
    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);
}
void decryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16];
    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);
}

786-Secure, Long-Range LoRa Chat Device Heltec WiFi LoRa 32 with buzzer

Langue: C++

/*
ESP32 Project: Build a Secure, Long-Range LoRa Chat Device Heltec WiFi LoRa 32

File: Heltec_ESP32_LoRa_V3_chat_TX_RX_buzzer.ino
written on 29 Jun, 2025 by Ahmad Shamshiri www.Roboajx.com
 * Please watch the tutorial video at: https://youtu.be/IsOSvrF60J4
 * Resources page for this video: https://robojax.com/RJT642
 
 * =====================================================================
 * ARDUINO CODE DESCRIPTION: SECURE LoRa  Keyboard Transceiver (chat system)
 * =====================================================================
 * 
 * HARDWARE COMPONENTS:
 * -------------------
 *  - Main Controller: Heltec WiFi LoRa 32 V3
 *  - Enclosure: Meshnology N33 case with 3000mAh battery
 *  - Input: Rotary encoder with push-button
 *  - Audiable: Active buzzer (connectedt o pin 40)
 *  - Feedback: Built-in OLED display
 * 
 * SYSTEM FUNCTIONALITY:
 * -------------------
  NEW CONTROLS:
  - Rotate Knob:         Select character.
  - Short Press (Click): Add selected character.
  - Long Press (Hold):   Insert a space (like a spacebar).
  - Double Click:        Backspace.
 * 
 * [2] SECURE WIRELESS TRANSMISSION:
 *     - All message  encrypted before LoRa transmission
 *     - Home position command transmitted as special secure packet
 *     - Uses 433MHz/915MHZ LoRa band for reliable communication
 * 
 * [3] POWER MANAGEMENT:
 *     - Optimized for battery operation (3000mAh)
 *     - Low-power modes between transmissions
 * 
 * FOR COMPLETE SETUP INSTRUCTIONS:
 * Please watch the tutorial video at: https://youtu.be/IsOSvrF60J4
 * Resources page for this video: https://robojax.com/RJT642
 * =====================================================================


 * DISCLAIMER:
 * This code is provided "AS IS" without warranty of any kind. The author 
 * shall not be held liable for any damages arising from the use of this code.
 * 
 * LICENSE:
 * This work is licensed under the GNU General Public License v3.0 
 * Permissions beyond the scope of this license may be available at Robojax.com
 * 
 * SHARING TERMS:
 * You are free to share, copy and modify this code for non-commercial purposes
 * PROVIDED you:
 * 1. Keep this entire comment block intact with the original code
 * 2. Include the original Robojax.com link
 * 3. Keep the YouTube tutorial link (if applicable)
 * 4. Clearly indicate any modifications made
 * 

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

// Core Heltec and display libraries
#include <Wire.h>
#include "HT_SSD1306Wire.h"
#include "WiFi.h"

// LoRa and security libraries
#include "LoRaWan_APP.h"
#include "mbedtls/aes.h"
#include <cstring>

// The user-approved Rotary Encoder library
#include "AiEsp32RotaryEncoder.h"

// --- PIN DEFINITIONS & CONFIGURATION ---
static SSD1306Wire  display(0x3c, 500000, SDA_OLED, SCL_OLED, GEOMETRY_128_64, RST_OLED);

#define ROTARY_ENCODER_A_PIN 5 //pin A of rotary encoder
#define ROTARY_ENCODER_B_PIN 6 //pin B of rotary encoder
#define ROTARY_ENCODER_BUTTON_PIN 4 //switch pin of rotary encoder

#define BUZZER_PIN 40 //the buzzer pin or relay to be triggered
const bool DEBUG = false;

#define RF_FREQUENCY 915432000 //operating frequency of LoRa
#define TX_OUTPUT_POWER 2 //output power should be between 2 to 21 in dBm. 
const char *userKey = "wahJ8uy$gt~_3r";//secureity key for private communication

#define ROTARY_ENCODER_VCC_PIN -1
#define ROTARY_ENCODER_STEPS 4

// --- LORA PARAMETERS ---
#define LORA_BANDWIDTH 0
#define LORA_SPREADING_FACTOR 7
#define LORA_CODINGRATE 1
#define LORA_PREAMBLE_LENGTH 8
#define LORA_SYMBOL_TIMEOUT 0
#define LORA_FIX_LENGTH_PAYLOAD_ON false
#define LORA_IQ_INVERSION_ON false
#define BUFFER_SIZE 256

#define LOOP_DELAY 10
// Buzzer state variables
unsigned long buzzerStartTime = 0;
bool isBuzzerActive = false;
int beepPhase = 0;  // 0=idle, 1=first beep, 2=pause, 3=second beep

#define USER_BUTTON_PIN 0
// --- GLOBAL VARIABLES & STATE ---
enum AppState { COMPOSING, READING };
AppState currentState = COMPOSING;
String messageToCompose = "";
String lastReceivedMessage = "No messages yet.";
bool hasUnreadMessage = false;
volatile bool newPacketAvailable = false;
char rxpacket[BUFFER_SIZE];
AiEsp32RotaryEncoder rotaryEncoder = AiEsp32RotaryEncoder(ROTARY_ENCODER_A_PIN, ROTARY_ENCODER_B_PIN, ROTARY_ENCODER_BUTTON_PIN, ROTARY_ENCODER_VCC_PIN, ROTARY_ENCODER_STEPS);
const char* charset = " ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.,!?>";
char selectedChar;
static RadioEvents_t RadioEvents;
bool lora_idle = true;

mbedtls_aes_context aes;
unsigned long shortPressAfterMiliseconds = 50;
unsigned long longPressAfterMiliseconds = 1000;
unsigned long doubleClickTimeout = 400;
static unsigned long buttonDownTime = 0;
static unsigned long buttonUpTime = 0;
static bool buttonWasDown = false;
static bool doubleClickWaiting = false;

// --- FUNCTION PROTOTYPES ---
void OnTxDone(void);
void OnTxTimeout(void);
void OnRxDone(uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr);
void encryptAES(uint8_t *data, const char *key);
void decryptAES(uint8_t *data, const char *key);
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize);
void updateDisplay();
void sendData();
void VextON(void);
void processButton();
void buzzer();
void updateBuzzer();


// --- INTERRUPT SERVICE ROUTINES ---
void IRAM_ATTR readEncoderISR() {
  rotaryEncoder.readEncoder_ISR();
}

// --- BUTTON HANDLER ACTIONS ---
void on_button_short_click() {
  if (currentState != COMPOSING) return;
  if (selectedChar == '>') {
      sendData();
  } else {
    messageToCompose += selectedChar;
  }
  updateDisplay();
}
void on_button_long_click() {
  if (currentState != COMPOSING) return;
  messageToCompose += " ";
  updateDisplay();
}
void on_button_double_click() {
  if (currentState != COMPOSING) return;
  if (messageToCompose.length() > 0) {
    messageToCompose.remove(messageToCompose.length() - 1);
  }
  updateDisplay();
}

// --- SETUP ---
void setup() {
  Serial.begin(115200);
  Serial.println("LoRa Keyboard Transceiver - By Robojax");

  VextON();
  delay(100);
  Mcu.begin(HELTEC_BOARD,SLOW_CLK_TPYE);
  WiFi.mode(WIFI_OFF);
  btStop();

  display.init();
  display.setFont(ArialMT_Plain_10);

  rotaryEncoder.begin();
  rotaryEncoder.setup(readEncoderISR);
  rotaryEncoder.setBoundaries(0, strlen(charset) - 1, true);
  rotaryEncoder.disableAcceleration();

  pinMode(USER_BUTTON_PIN, INPUT_PULLUP);
  pinMode(BUZZER_PIN, OUTPUT);

  RadioEvents.TxDone = OnTxDone;
  RadioEvents.TxTimeout = OnTxTimeout;
  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);
  
  updateDisplay();
}

// --- MAIN LOOP ---
void loop() {
  if(lora_idle) {
    lora_idle = false;
    if(DEBUG)
    {
    Serial.println("Entering RX mode...");
    }

    Radio.Rx(0);
  }
  Radio.IrqProcess(); 

  if (newPacketAvailable) {
    newPacketAvailable = false;
    hasUnreadMessage = true;
    lastReceivedMessage = String(rxpacket);
    if(DEBUG)
    {
    Serial.print("Received Decrypted Message: ");
    Serial.println(lastReceivedMessage);
    }
    updateDisplay();
    buzzer();
  }
  
  if (currentState == COMPOSING) {
    if (rotaryEncoder.encoderChanged()) {
      updateDisplay();
    }
    processButton();
  }
  
  if (digitalRead(USER_BUTTON_PIN) == LOW) {
    delay(50);
    if (digitalRead(USER_BUTTON_PIN) == LOW) {
      if (currentState == COMPOSING) {
        if (lastReceivedMessage != "No messages yet.") {
          currentState = READING;
          hasUnreadMessage = false;
          updateDisplay();
        }
      } else {
        currentState = COMPOSING;
        updateDisplay();
      }
      while (digitalRead(USER_BUTTON_PIN) == LOW);
    }
  }
  
  updateBuzzer();  // Update buzzer state (non-blocking)
  delay(LOOP_DELAY);  // Your 10ms loop delay
}

// --- LORA EVENT HANDLERS & HELPERS ---
void OnTxDone(void) {
    if(DEBUG)
    {
      Serial.println("TX done.");
    }
  Radio.Sleep();
  lora_idle = true;
}
void OnTxTimeout(void) {
    if(DEBUG)
    {  
      Serial.println("TX Timeout.");
    }
  Radio.Sleep();
  lora_idle = true;
}
void OnRxDone(uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr) {
    Radio.Sleep();
    memset(rxpacket, 0, sizeof(rxpacket));
    memcpy(rxpacket, payload, size > BUFFER_SIZE ? BUFFER_SIZE : size);
    decryptAES((uint8_t*)rxpacket, userKey);
    newPacketAvailable = true;
    lora_idle = true;
}

void sendData() {
  if (messageToCompose.length() > 0) {
    lora_idle = false; 
    
    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);

    uint8_t data[BUFFER_SIZE];
    memset(data, 0, BUFFER_SIZE);
    strncpy((char*)data, messageToCompose.c_str(), BUFFER_SIZE - 1);
    
    encryptAES(data, userKey);
    if(DEBUG)
    {
    Serial.print("Sending message: ");
    Serial.println(messageToCompose);
    }

    Radio.Send(data, 16);
    
    messageToCompose = "";
  }
}

// --- DISPLAY & BUTTON LOGIC ---
void updateDisplay() {
  display.clear();
  display.setTextAlignment(TEXT_ALIGN_LEFT);

  if (currentState == COMPOSING) {
    selectedChar = charset[rotaryEncoder.readEncoder()];
    display.setFont(ArialMT_Plain_10);
    
    // --- THIS IS THE FIX for the notification ---
    String msgLabel;
    if (hasUnreadMessage) {
        msgLabel = ">> NEW MSG <<"; // Make the notification very obvious
    } else {
        msgLabel = "Msg:";
    }
    display.drawStringMaxWidth(0, 0, 128, msgLabel + " " + messageToCompose);

    display.setFont(ArialMT_Plain_16);
    int16_t labelWidth = display.getStringWidth("Select: ");
    display.drawString(0, 35, "Select: ");
    display.setFont(ArialMT_Plain_24);
    display.drawString(labelWidth, 32, String(selectedChar));
  } else { // currentState == READING
    display.setFont(ArialMT_Plain_16);
    display.drawString(0, 0, "Received:");
    display.setFont(ArialMT_Plain_10);
    display.drawStringMaxWidth(0, 18, 128, lastReceivedMessage);
  }
  
  display.display();
}

void processButton() {
    if (doubleClickWaiting && (millis() - buttonUpTime > doubleClickTimeout)) {
        doubleClickWaiting = false;
        on_button_short_click();
    }
    bool isButtonDown = rotaryEncoder.isEncoderButtonDown();
    if (isButtonDown && !buttonWasDown) {
        buttonDownTime = millis();
        buttonWasDown = true;
    } 
    else if (!isButtonDown && buttonWasDown) {
        unsigned long pressDuration = millis() - buttonDownTime;
        if (pressDuration >= longPressAfterMiliseconds) {
            on_button_long_click();
            doubleClickWaiting = false;
        } 
        else if (pressDuration >= shortPressAfterMiliseconds) {
            if (doubleClickWaiting) {
                on_button_double_click();
                doubleClickWaiting = false;
            } else {
                doubleClickWaiting = true;
                buttonUpTime = millis();
            }
        }
        buttonWasDown = false;
    }
}


void buzzer()
{
  if (!isBuzzerActive) {
    isBuzzerActive = true;
    buzzerStartTime = millis();  // Start buzzer sequence
    beepPhase = 1;              // First beep
    digitalWrite(BUZZER_PIN, HIGH);
  }
}
void updateBuzzer() {
  if (!isBuzzerActive) return;

  unsigned long currentTime = millis();
  unsigned long elapsed = currentTime - buzzerStartTime;

  switch (beepPhase) {
    case 1: // First beep (300ms ON)
      if (elapsed >= 300) {
        digitalWrite(BUZZER_PIN, LOW);
        buzzerStartTime = currentTime;
        beepPhase = 2;  // Move to pause
      }
      break;

    case 2: // Pause (200ms OFF)
      if (elapsed >= 200) {
        digitalWrite(BUZZER_PIN, HIGH);
        buzzerStartTime = currentTime;
        beepPhase = 3;  // Move to second beep
      }
      break;

    case 3: // Second beep (300ms ON)
      if (elapsed >= 300) {
        digitalWrite(BUZZER_PIN, LOW);
        isBuzzerActive = false;  // Reset
        beepPhase = 0;
      }
      break;
  }
}
// --- UTILITIES ---
void VextON(void) {
  pinMode(Vext,OUTPUT);
  digitalWrite(Vext, LOW);
}
void processKey(const char *userKey, uint8_t *processedKey, size_t keySize) {
    memset(processedKey, 0, keySize);
    size_t len = strlen(userKey);
    if (len > keySize) len = keySize;
    memcpy(processedKey, userKey, len);
}
void encryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16];
    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);
}
void decryptAES(uint8_t *data, const char *key) {
    uint8_t processedKey[16];
    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);
}

Common Course Links

Common Course Files

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L'extérieur
Purchase Wi-Fi LoRa 32 from Meshnology
meshnology.com

Fichiers📁

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Robojax Heltec WiFi LoRa 32 Library Version 1.1.0 20250703
Robojax_HeltecLoRa32_1.1.0_20250702.zip 0.09 MB
ESP32-WROOM-32E Datasheet
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ESP32-WROOM-32E-datasheet.pdf 1.16 MB

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