Support ESPNow and improve documentation

examples/simple_repeater/main.cpp

@@ -80,30 +80,36 @@
 
 #ifdef WITH_RS232_BRIDGE
 #include "helpers/bridges/RS232Bridge.h"
+#define WITH_BRIDGE
 #endif
 
-#define REQ_TYPE_GET_STATUS          0x01   // same as _GET_STATS
-#define REQ_TYPE_KEEP_ALIVE          0x02
-#define REQ_TYPE_GET_TELEMETRY_DATA  0x03
+#ifdef WITH_ESPNOW_BRIDGE
+#include "helpers/bridges/ESPNowBridge.h"
+#define WITH_BRIDGE
+#endif
 
-#define RESP_SERVER_LOGIN_OK      0   // response to ANON_REQ
+#define REQ_TYPE_GET_STATUS         0x01 // same as _GET_STATS
+#define REQ_TYPE_KEEP_ALIVE         0x02
+#define REQ_TYPE_GET_TELEMETRY_DATA 0x03
 
-struct RepeaterStats {
-  uint16_t batt_milli_volts;
-  uint16_t curr_tx_queue_len;
-  int16_t  noise_floor;
-  int16_t  last_rssi;
-  uint32_t n_packets_recv;
-  uint32_t n_packets_sent;
-  uint32_t total_air_time_secs;
-  uint32_t total_up_time_secs;
-  uint32_t n_sent_flood, n_sent_direct;
-  uint32_t n_recv_flood, n_recv_direct;
-  uint16_t err_events;                // was 'n_full_events'
-  int16_t  last_snr;   // x 4
-  uint16_t n_direct_dups, n_flood_dups;
-  uint32_t total_rx_air_time_secs;
-};
+#define RESP_SERVER_LOGIN_OK        0 // response to ANON_REQ
+
+  struct RepeaterStats {
+    uint16_t batt_milli_volts;
+    uint16_t curr_tx_queue_len;
+    int16_t noise_floor;
+    int16_t last_rssi;
+    uint32_t n_packets_recv;
+    uint32_t n_packets_sent;
+    uint32_t total_air_time_secs;
+    uint32_t total_up_time_secs;
+    uint32_t n_sent_flood, n_sent_direct;
+    uint32_t n_recv_flood, n_recv_direct;
+    uint16_t err_events; // was 'n_full_events'
+    int16_t last_snr;    // x 4
+    uint16_t n_direct_dups, n_flood_dups;
+    uint32_t total_rx_air_time_secs;
+  };
 
 struct ClientInfo {
   mesh::Identity id;
@@ -118,7 +124,7 @@ struct ClientInfo {
   #define MAX_CLIENTS           32
 #endif
 
-#ifdef WITH_RS232_BRIDGE
+#ifdef WITH_BRIDGE
 AbstractBridge* bridge;
 #endif
 
@@ -308,7 +314,7 @@ protected:
     }
   }
   void logTx(mesh::Packet* pkt, int len) override {
-#ifdef WITH_RS232_BRIDGE
+#ifdef WITH_BRIDGE
     bridge->onPacketTransmitted(pkt);
 #endif
     if (_logging) {
@@ -576,8 +582,14 @@ public:
      : mesh::Mesh(radio, ms, rng, rtc, *new StaticPoolPacketManager(32), tables),
       _cli(board, rtc, &_prefs, this), telemetry(MAX_PACKET_PAYLOAD - 4)
   {
-#ifdef WITH_RS232_BRIDGE
+#ifdef WITH_BRIDGE
+#if defined(WITH_RS232_BRIDGE)
     bridge = new RS232Bridge(WITH_RS232_BRIDGE, _mgr, &rtc);
+#elif defined(WITH_ESPNOW_BRIDGE)
+    bridge = new ESPNowBridge(_mgr, &rtc);
+#else
+#error "You must choose either RS232 or ESPNow bridge"
+#endif
 #endif
     memset(known_clients, 0, sizeof(known_clients));
     next_local_advert = next_flood_advert = 0;
@@ -779,7 +791,7 @@ public:
   }
 
   void loop() {
-#ifdef WITH_RS232_BRIDGE
+#ifdef WITH_BRIDGE
     bridge->loop();
 #endif
 
@@ -831,7 +843,7 @@ void setup() {
   Serial.begin(115200);
   delay(1000);
 
-#ifdef WITH_RS232_BRIDGE
+#ifdef WITH_BRIDGE
   bridge->begin();
 #endif
 

src/helpers/bridges/ESPNowBridge.cpp

@@ -0,0 +1,184 @@
+#include "ESPNowBridge.h"
+
+#include <RTClib.h>
+#include <WiFi.h>
+#include <esp_wifi.h>
+
+#ifdef WITH_ESPNOW_BRIDGE
+
+// Static member to handle callbacks
+ESPNowBridge *ESPNowBridge::_instance = nullptr;
+
+// Static callback wrappers
+void ESPNowBridge::recv_cb(const uint8_t *mac, const uint8_t *data, int len) {
+  if (_instance) {
+    _instance->onDataRecv(mac, data, len);
+  }
+}
+
+void ESPNowBridge::send_cb(const uint8_t *mac, esp_now_send_status_t status) {
+  if (_instance) {
+    _instance->onDataSent(mac, status);
+  }
+}
+
+// Fletcher16 checksum calculation
+static uint16_t fletcher16(const uint8_t *data, size_t len) {
+  uint16_t sum1 = 0;
+  uint16_t sum2 = 0;
+
+  while (len--) {
+    sum1 = (sum1 + *data++) % 255;
+    sum2 = (sum2 + sum1) % 255;
+  }
+
+  return (sum2 << 8) | sum1;
+}
+
+ESPNowBridge::ESPNowBridge(mesh::PacketManager *mgr, mesh::RTCClock *rtc)
+    : _mgr(mgr), _rtc(rtc), _rx_buffer_pos(0) {
+  _instance = this;
+}
+
+void ESPNowBridge::begin() {
+  // Initialize WiFi in station mode
+  WiFi.mode(WIFI_STA);
+
+  // Initialize ESP-NOW
+  if (esp_now_init() != ESP_OK) {
+    Serial.printf("%s: ESPNOW BRIDGE: Error initializing ESP-NOW\n", getLogDateTime());
+    return;
+  }
+
+  // Register callbacks
+  esp_now_register_recv_cb(recv_cb);
+  esp_now_register_send_cb(send_cb);
+
+  // Add broadcast peer
+  esp_now_peer_info_t peerInfo = {};
+  memset(&peerInfo, 0, sizeof(peerInfo));
+  memset(peerInfo.peer_addr, 0xFF, ESP_NOW_ETH_ALEN); // Broadcast address
+  peerInfo.channel = 0;
+  peerInfo.encrypt = false;
+
+  if (esp_now_add_peer(&peerInfo) != ESP_OK) {
+    Serial.printf("%s: ESPNOW BRIDGE: Failed to add broadcast peer\n", getLogDateTime());
+    return;
+  }
+}
+
+void ESPNowBridge::loop() {
+  // Nothing to do here - ESP-NOW is callback based
+}
+
+void ESPNowBridge::xorCrypt(uint8_t *data, size_t len) {
+  size_t keyLen = strlen(_secret);
+  for (size_t i = 0; i < len; i++) {
+    data[i] ^= _secret[i % keyLen];
+  }
+}
+
+void ESPNowBridge::onDataRecv(const uint8_t *mac, const uint8_t *data, int len) {
+  // Ignore packets that are too small
+  if (len < 3) {
+#if MESH_PACKET_LOGGING
+    Serial.printf("%s: ESPNOW BRIDGE: RX packet too small, len=%d\n", getLogDateTime(), len);
+#endif
+    return;
+  }
+
+  // Check packet header magic
+  if (data[0] != ESPNOW_HEADER_MAGIC) {
+#if MESH_PACKET_LOGGING
+    Serial.printf("%s: ESPNOW BRIDGE: RX invalid magic 0x%02X\n", getLogDateTime(), data[0]);
+#endif
+    return;
+  }
+
+  // Make a copy we can decrypt
+  uint8_t decrypted[MAX_ESPNOW_PACKET_SIZE];
+  memcpy(decrypted, data + 1, len - 1); // Skip magic byte
+
+  // Try to decrypt
+  xorCrypt(decrypted, len - 1);
+
+  // Validate checksum
+  uint16_t received_checksum = (decrypted[0] << 8) | decrypted[1];
+  uint16_t calculated_checksum = fletcher16(decrypted + 2, len - 3);
+
+  if (received_checksum != calculated_checksum) {
+    // Failed to decrypt - likely from a different network
+#if MESH_PACKET_LOGGING
+    Serial.printf("%s: ESPNOW BRIDGE: RX checksum mismatch, rcv=0x%04X calc=0x%04X\n", getLogDateTime(),
+                  received_checksum, calculated_checksum);
+#endif
+    return;
+  }
+
+#if MESH_PACKET_LOGGING
+  Serial.printf("%s: ESPNOW BRIDGE: RX, len=%d\n", getLogDateTime(), len - 3);
+#endif
+
+  // Create mesh packet
+  mesh::Packet *pkt = _instance->_mgr->allocNew();
+  if (!pkt) return;
+
+  if (pkt->readFrom(decrypted + 2, len - 3)) {
+    _instance->onPacketReceived(pkt);
+  } else {
+    _instance->_mgr->free(pkt);
+  }
+}
+
+void ESPNowBridge::onDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
+  // Could add transmission error handling here if needed
+}
+
+void ESPNowBridge::onPacketReceived(mesh::Packet *packet) {
+  if (!_seen_packets.hasSeen(packet)) {
+    _mgr->queueInbound(packet, 0);
+  } else {
+    _mgr->free(packet);
+  }
+}
+
+void ESPNowBridge::onPacketTransmitted(mesh::Packet *packet) {
+  if (!_seen_packets.hasSeen(packet)) {
+    uint8_t buffer[MAX_ESPNOW_PACKET_SIZE];
+    buffer[0] = ESPNOW_HEADER_MAGIC;
+
+    // Write packet to buffer starting after magic byte and checksum
+    uint16_t len = packet->writeTo(buffer + 3);
+
+    // Calculate and add checksum
+    uint16_t checksum = fletcher16(buffer + 3, len);
+    buffer[1] = (checksum >> 8) & 0xFF;
+    buffer[2] = checksum & 0xFF;
+
+    // Encrypt payload (not including magic byte)
+    xorCrypt(buffer + 1, len + 2);
+
+    // Broadcast using ESP-NOW
+    uint8_t broadcastAddress[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+    esp_err_t result = esp_now_send(broadcastAddress, buffer, len + 3);
+
+#if MESH_PACKET_LOGGING
+    if (result == ESP_OK) {
+      Serial.printf("%s: ESPNOW BRIDGE: TX, len=%d\n", getLogDateTime(), len);
+    } else {
+      Serial.printf("%s: ESPNOW BRIDGE: TX FAILED!\n", getLogDateTime());
+    }
+#endif
+  }
+}
+
+const char *ESPNowBridge::getLogDateTime() {
+  static char tmp[32];
+  uint32_t now = _rtc->getCurrentTime();
+  DateTime dt = DateTime(now);
+  sprintf(tmp, "%02d:%02d:%02d - %d/%d/%d U", dt.hour(), dt.minute(), dt.second(), dt.day(), dt.month(),
+          dt.year());
+  return tmp;
+}
+
+#endif

src/helpers/bridges/ESPNowBridge.h

@@ -0,0 +1,170 @@
+#pragma once
+
+#include "MeshCore.h"
+#include "esp_now.h"
+#include "helpers/AbstractBridge.h"
+#include "helpers/SimpleMeshTables.h"
+
+#ifdef WITH_ESPNOW_BRIDGE
+
+#ifndef WITH_ESPNOW_BRIDGE_SECRET
+#error WITH_ESPNOW_BRIDGE_SECRET must be defined to use ESPNowBridge
+#endif
+
+/**
+ * @brief Bridge implementation using ESP-NOW protocol for packet transport
+ *
+ * This bridge enables mesh packet transport over ESP-NOW, a connectionless communication
+ * protocol provided by Espressif that allows ESP32 devices to communicate directly
+ * without WiFi router infrastructure.
+ *
+ * Features:
+ * - Broadcast-based communication (all bridges receive all packets)
+ * - Network isolation using XOR encryption with shared secret
+ * - Duplicate packet detection using SimpleMeshTables tracking
+ * - Maximum packet size of 250 bytes (ESP-NOW limitation)
+ *
+ * Packet Structure:
+ * [1 byte]  Magic Header (0xAB) - Used to identify ESPNowBridge packets
+ * [2 bytes] Fletcher-16 checksum of encrypted payload (calculated over payload only)
+ * [n bytes] Encrypted payload containing the mesh packet
+ *
+ * The Fletcher-16 checksum is used to validate packet integrity and detect
+ * corrupted or tampered packets. It's calculated over the encrypted payload
+ * and provides a simple but effective way to verify packets are both
+ * uncorrupted and from the same network (since the checksum is calculated
+ * after encryption).
+ *
+ * Configuration:
+ * - Define WITH_ESPNOW_BRIDGE to enable this bridge
+ * - Define WITH_ESPNOW_BRIDGE_SECRET with a string to set the network encryption key
+ *
+ * Network Isolation:
+ * Multiple independent mesh networks can coexist by using different
+ * WITH_ESPNOW_BRIDGE_SECRET values. Packets encrypted with a different key will
+ * fail the checksum validation and be discarded.
+ */
+class ESPNowBridge : public AbstractBridge {
+private:
+  static ESPNowBridge *_instance;
+  static void recv_cb(const uint8_t *mac, const uint8_t *data, int len);
+  static void send_cb(const uint8_t *mac, esp_now_send_status_t status);
+
+  /** Packet manager for allocating and queuing mesh packets */
+  mesh::PacketManager *_mgr;
+
+  /** RTC clock for timestamping debug messages */
+  mesh::RTCClock *_rtc;
+
+  /** Tracks seen packets to prevent loops in broadcast communications */
+  SimpleMeshTables _seen_packets;
+
+  /**
+   * Maximum ESP-NOW packet size (250 bytes)
+   * This is a hardware limitation of ESP-NOW protocol:
+   * - ESP-NOW header: 20 bytes
+   * - Max payload: 250 bytes
+   * Source: ESP-NOW API documentation
+   */
+  static const size_t MAX_ESPNOW_PACKET_SIZE = 250;
+
+  /**
+   * Magic byte to identify ESPNowBridge packets (0xAB)
+   */
+  static const uint8_t ESPNOW_HEADER_MAGIC = 0xAB;
+
+  /** Buffer for receiving ESP-NOW packets */
+  uint8_t _rx_buffer[MAX_ESPNOW_PACKET_SIZE];
+
+  /** Current position in receive buffer */
+  size_t _rx_buffer_pos;
+
+  /**
+   * Network encryption key from build define
+   * Must be defined with WITH_ESPNOW_BRIDGE_SECRET
+   * Used for XOR encryption to isolate different mesh networks
+   */
+  const char *_secret = WITH_ESPNOW_BRIDGE_SECRET;
+
+  /**
+   * Performs XOR encryption/decryption of data
+   *
+   * Uses WITH_ESPNOW_BRIDGE_SECRET as the key in a simple XOR operation.
+   * The same operation is used for both encryption and decryption.
+   * While not cryptographically secure, it provides basic network isolation.
+   *
+   * @param data Pointer to data to encrypt/decrypt
+   * @param len Length of data in bytes
+   */
+  void xorCrypt(uint8_t *data, size_t len);
+
+  /**
+   * ESP-NOW receive callback
+   * Called by ESP-NOW when a packet is received
+   *
+   * @param mac Source MAC address
+   * @param data Received data
+   * @param len Length of received data
+   */
+  void onDataRecv(const uint8_t *mac, const uint8_t *data, int len);
+
+  /**
+   * ESP-NOW send callback
+   * Called by ESP-NOW after a transmission attempt
+   *
+   * @param mac_addr Destination MAC address
+   * @param status Transmission status
+   */
+  void onDataSent(const uint8_t *mac_addr, esp_now_send_status_t status);
+
+public:
+  /**
+   * Constructs an ESPNowBridge instance
+   *
+   * @param mgr PacketManager for allocating and queuing packets
+   * @param rtc RTCClock for timestamping debug messages
+   */
+  ESPNowBridge(mesh::PacketManager *mgr, mesh::RTCClock *rtc);
+
+  /**
+   * Initializes the ESP-NOW bridge
+   *
+   * - Configures WiFi in station mode
+   * - Initializes ESP-NOW protocol
+   * - Registers callbacks
+   * - Sets up broadcast peer
+   */
+  void begin() override;
+
+  /**
+   * Main loop handler
+   * ESP-NOW is callback-based, so this is currently empty
+   */
+  void loop() override;
+
+  /**
+   * Called when a packet is received via ESP-NOW
+   * Queues the packet for mesh processing if not seen before
+   *
+   * @param packet The received mesh packet
+   */
+  void onPacketReceived(mesh::Packet *packet) override;
+
+  /**
+   * Called when a packet needs to be transmitted via ESP-NOW
+   * Encrypts and broadcasts the packet if not seen before
+   *
+   * @param packet The mesh packet to transmit
+   */
+  void onPacketTransmitted(mesh::Packet *packet) override;
+
+  /**
+   * Gets formatted date/time string for logging
+   * Format: "HH:MM:SS - DD/MM/YYYY U"
+   *
+   * @return Formatted date/time string
+   */
+  const char *getLogDateTime();
+};
+
+#endif

src/helpers/bridges/RS232Bridge.cpp

@@ -4,8 +4,9 @@
 
 #ifdef WITH_RS232_BRIDGE
 
-// Fletcher-16
-// https://en.wikipedia.org/wiki/Fletcher%27s_checksum
+// Static Fletcher-16 checksum calculation
+// Based on: https://en.wikipedia.org/wiki/Fletcher%27s_checksum
+// Used to verify data integrity of received packets
 inline static uint16_t fletcher16(const uint8_t *bytes, const size_t len) {
   uint8_t sum1 = 0, sum2 = 0;
 

src/helpers/bridges/RS232Bridge.h

@@ -7,28 +7,87 @@
 #ifdef WITH_RS232_BRIDGE
 
 /**
- * @brief A bridge implementation that uses a serial port to connect two mesh networks.
+ * @brief Bridge implementation using RS232/UART protocol for packet transport
+ *
+ * This bridge enables mesh packet transport over serial/UART connections,
+ * allowing nodes to communicate over wired serial links. It implements a simple
+ * packet framing protocol with checksums for reliable transfer.
+ *
+ * Features:
+ * - Point-to-point communication over hardware UART
+ * - Fletcher-16 checksum for data integrity verification 
+ * - Magic header for packet synchronization
+ * - Configurable RX/TX pins via build defines
+ * - Baud rate fixed at 115200
+ *
+ * Packet Structure:
+ * [2 bytes] Magic Header (0xCAFE) - Used to identify start of packet
+ * [2 bytes] Fletcher-16 checksum - Data integrity check
+ * [1 byte]  Payload length
+ * [n bytes] Packet payload
+ *
+ * The Fletcher-16 checksum is used to validate packet integrity and detect
+ * corrupted or malformed packets. It provides error detection capabilities
+ * suitable for serial communication where noise or timing issues could
+ * corrupt data.
+ *
+ * Configuration:
+ * - Define WITH_RS232_BRIDGE to enable this bridge
+ * - Define WITH_RS232_BRIDGE_RX with the RX pin number
+ * - Define WITH_RS232_BRIDGE_TX with the TX pin number
+ *
+ * Platform Support:
+ * - ESP32 targets
+ * - NRF52 targets
+ * - RP2040 targets 
+ * - STM32 targets
  */
 class RS232Bridge : public AbstractBridge {
 public:
   /**
-   * @brief Construct a new Serial Bridge object
-   * 
-   * @param serial The serial port to use for the bridge.
-   * @param mgr A pointer to the packet manager.
-   * @param rtc A pointer to the RTC clock.
+   * @brief Constructs an RS232Bridge instance
+   *
+   * @param serial The hardware serial port to use
+   * @param mgr PacketManager for allocating and queuing packets
+   * @param rtc RTCClock for timestamping debug messages
    */
   RS232Bridge(Stream& serial, mesh::PacketManager* mgr, mesh::RTCClock* rtc);
+
+  /**
+   * Initializes the RS232 bridge
+   * 
+   * - Configures UART pins based on platform
+   * - Sets baud rate to 115200
+   */
   void begin() override;
+
+  /**
+   * @brief Main loop handler
+   * Processes incoming serial data and builds packets
+   */
   void loop() override;
+
+  /**
+   * @brief Called when a packet needs to be transmitted over serial
+   * Formats and sends the packet with proper framing
+   *
+   * @param packet The mesh packet to transmit
+   */
   void onPacketTransmitted(mesh::Packet* packet) override;
+
+  /**
+   * @brief Called when a complete packet has been received from serial
+   * Queues the packet for mesh processing if checksum is valid
+   * 
+   * @param packet The received mesh packet
+   */
   void onPacketReceived(mesh::Packet* packet) override;
 
 private:
+  /** Helper function to get formatted timestamp for logging */
   const char* getLogDateTime();
-  /**
-   * @brief The 2-byte magic word used to signify the start of a packet.
-   */
+
+  /** Magic number to identify start of RS232 packets (0xCAFE) */
   static constexpr uint16_t SERIAL_PKT_MAGIC = 0xCAFE;
 
   /**

variants/lilygo_tlora_v2_1/platformio.ini

@@ -64,29 +64,6 @@ lib_deps =
   ${LilyGo_TLora_V2_1_1_6.lib_deps}
   ${esp32_ota.lib_deps}
 
-[env:LilyGo_TLora_V2_1_1_6_repeater_bridge]
-extends = LilyGo_TLora_V2_1_1_6
-build_src_filter = ${LilyGo_TLora_V2_1_1_6.build_src_filter}
-  +<helpers/ui/SSD1306Display.cpp>
-  +<helpers/bridges/RS232Bridge.cpp>
-  +<../examples/simple_repeater>
-build_flags =
-  ${LilyGo_TLora_V2_1_1_6.build_flags}
-  -D ADVERT_NAME='"TLora-V2.1-1.6 Bridge"'
-  -D ADVERT_LAT=0.0
-  -D ADVERT_LON=0.0
-  -D ADMIN_PASSWORD='"password"'
-  -D MAX_NEIGHBOURS=8
-  -D WITH_RS232_BRIDGE=Serial2
-  -D WITH_RS232_BRIDGE_RX=34
-  -D WITH_RS232_BRIDGE_TX=25
-  -D MESH_PACKET_LOGGING=1
-;  -D MESH_DEBUG=1
-;  -D CORE_DEBUG_LEVEL=3
-lib_deps =
-  ${LilyGo_TLora_V2_1_1_6.lib_deps}
-  ${esp32_ota.lib_deps}
-
 [env:LilyGo_TLora_V2_1_1_6_terminal_chat]
 extends = LilyGo_TLora_V2_1_1_6
 build_flags =
@@ -179,3 +156,51 @@ build_src_filter = ${LilyGo_TLora_V2_1_1_6.build_src_filter}
 lib_deps =
   ${LilyGo_TLora_V2_1_1_6.lib_deps}
   densaugeo/base64 @ ~1.4.0
+
+;
+; Repeater Bridges
+;
+[env:LilyGo_TLora_V2_1_1_6_bridge_rs232]
+extends = LilyGo_TLora_V2_1_1_6
+build_src_filter = ${LilyGo_TLora_V2_1_1_6.build_src_filter}
+  +<helpers/ui/SSD1306Display.cpp>
+  +<helpers/bridges/RS232Bridge.cpp>
+  +<../examples/simple_repeater>
+build_flags =
+  ${LilyGo_TLora_V2_1_1_6.build_flags}
+  -D ADVERT_NAME='"RS232 Bridge"'
+  -D ADVERT_LAT=0.0
+  -D ADVERT_LON=0.0
+  -D ADMIN_PASSWORD='"password"'
+  -D MAX_NEIGHBOURS=8
+  -D WITH_RS232_BRIDGE=Serial2
+  -D WITH_RS232_BRIDGE_RX=34
+  -D WITH_RS232_BRIDGE_TX=25
+  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+;  -D CORE_DEBUG_LEVEL=3
+lib_deps =
+  ${LilyGo_TLora_V2_1_1_6.lib_deps}
+  ${esp32_ota.lib_deps}
+
+[env:LilyGo_TLora_V2_1_1_6_bridge_espnow]
+extends = LilyGo_TLora_V2_1_1_6
+build_src_filter = ${LilyGo_TLora_V2_1_1_6.build_src_filter}
+  +<helpers/ui/SSD1306Display.cpp>
+  +<helpers/bridges/ESPNowBridge.cpp>
+  +<../examples/simple_repeater>
+build_flags =
+  ${LilyGo_TLora_V2_1_1_6.build_flags}
+  -D ADVERT_NAME='"ESPNow Bridge"'
+  -D ADVERT_LAT=0.0
+  -D ADVERT_LON=0.0
+  -D ADMIN_PASSWORD='"password"'
+  -D MAX_NEIGHBOURS=8
+  -D WITH_ESPNOW_BRIDGE=1
+  -D WITH_ESPNOW_BRIDGE_SECRET='"shared-secret"'
+  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+;  -D CORE_DEBUG_LEVEL=3
+lib_deps =
+  ${LilyGo_TLora_V2_1_1_6.lib_deps}
+  ${esp32_ota.lib_deps}