M5Nano C6(マスター)でESP-NOWで遊ぶ。




参考


https://qiita.com/caa45040/items/c4025a0669ad26bf916b


目的

まず、サンプルを改造して動かしてみる
(M5NanoC6を1台しかないため)
マスター NanoC6
スレーブ StampS3

いちおう、簡単な説明
ブロードキャスト　全部の機体に一斉放送して、
5秒毎にハローワールドとメッセージを投げる。
ハローワールドが受信できたら成功とみなす。

けっこう、NanoC6(ホストから送信)の本体が熱くなる



結果

(マスター)

![o_coq530.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/1000d4be-bf60-4734-fefd-7a4f1a9a39cb.jpeg)


(スレーブ)

![o_coq531.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/1f0f48a4-af2e-7605-1c04-e14b27063f7f.jpeg)


(マスターとスレーブ)

![o_coq532.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/27a35e6d-3906-d009-5994-1a0cb7b612e8.jpeg)

![o_coq533.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/840352/4a78298b-bfc3-5844-7bb6-9605766e61b9.jpeg)



プログラム

(マスター)



```c++

/*
    ESP-NOW Broadcast Master
    Lucas Saavedra Vaz - 2024

    This sketch demonstrates how to broadcast messages to all devices within the ESP-NOW network.
    This example is intended to be used with the ESP-NOW Broadcast Slave example.

    The master device will broadcast a message every 5 seconds to all devices within the network.
    This will be done using by registering a peer object with the broadcast address.

    The slave devices will receive the broadcasted messages and print them to the Serial Monitor.
*/

#include "ESP32_NOW.h"
#include "WiFi.h"

#include <esp_mac.h>  // For the MAC2STR and MACSTR macros

/* Definitions */

#define ESPNOW_WIFI_CHANNEL 1

/* Classes */

// Creating a new class that inherits from the ESP_NOW_Peer class is required.

class ESP_NOW_Broadcast_Peer : public ESP_NOW_Peer {
public:
  // Constructor of the class using the broadcast address
  ESP_NOW_Broadcast_Peer(uint8_t channel, wifi_interface_t iface, const uint8_t *lmk) : ESP_NOW_Peer(ESP_NOW.BROADCAST_ADDR, channel, iface, lmk) {}

  // Destructor of the class
  ~ESP_NOW_Broadcast_Peer() {
    remove();
  }

  // Function to properly initialize the ESP-NOW and register the broadcast peer
  bool begin() {
    if (!ESP_NOW.begin() || !add()) {
      log_e("Failed to initialize ESP-NOW or register the broadcast peer");
      return false;
    }
    return true;
  }

  // Function to send a message to all devices within the network
  bool send_message(const uint8_t *data, size_t len) {
    if (!send(data, len)) {
      log_e("Failed to broadcast message");
      return false;
    }
    return true;
  }
};

/* Global Variables */

uint32_t msg_count = 0;

// Create a broadcast peer object
ESP_NOW_Broadcast_Peer broadcast_peer(ESPNOW_WIFI_CHANNEL, WIFI_IF_STA, NULL);

/* Main */

void setup() {
  Serial.begin(115200);
  
  //while (!Serial) {
  //  delay(10);
  //}

  for(int i=0;i<30;i++){
    Serial.println("WiFi");
    delay(1000);
  }//for


  // Initialize the Wi-Fi module
  WiFi.mode(WIFI_STA);
  WiFi.setChannel(ESPNOW_WIFI_CHANNEL);
  while (!WiFi.STA.started()) {
    delay(100);
  }

  Serial.println("ESP-NOW Example - Broadcast Master");
  Serial.println("Wi-Fi parameters:");
  Serial.println("  Mode: STA");
  Serial.println("  MAC Address: " + WiFi.macAddress());
  Serial.printf("  Channel: %d\n", ESPNOW_WIFI_CHANNEL);

  // Register the broadcast peer
  if (!broadcast_peer.begin()) {
    Serial.println("Failed to initialize broadcast peer");
    Serial.println("Reebooting in 5 seconds...");
    delay(5000);
    ESP.restart();
  }

  Serial.println("Setup complete. Broadcasting messages every 5 seconds.");
}

void loop() {
  // Broadcast a message to all devices within the network
  char data[32];
  snprintf(data, sizeof(data), "Hello, World! #%lu", msg_count++);

  Serial.printf("Broadcasting message: %s\n", data);

  if (!broadcast_peer.send_message((uint8_t *)data, sizeof(data))) {
    Serial.println("Failed to broadcast message");
  }

  delay(5000);
}


```


(スレーブ)



```c++


/*
    ESP-NOW Broadcast Slave
    Lucas Saavedra Vaz - 2024

    This sketch demonstrates how to receive broadcast messages from a master device using the ESP-NOW protocol.

    The master device will broadcast a message every 5 seconds to all devices within the network.

    The slave devices will receive the broadcasted messages. If they are not from a known master, they will be registered as a new master
    using a callback function.
*/

#include "ESP32_NOW.h"
#include "WiFi.h"

#include <esp_mac.h>  // For the MAC2STR and MACSTR macros

#include <vector>

/* Definitions */

#define ESPNOW_WIFI_CHANNEL 1

/* Classes */

// Creating a new class that inherits from the ESP_NOW_Peer class is required.

class ESP_NOW_Peer_Class : public ESP_NOW_Peer {
public:
  // Constructor of the class
  ESP_NOW_Peer_Class(const uint8_t *mac_addr, uint8_t channel, wifi_interface_t iface, const uint8_t *lmk) : ESP_NOW_Peer(mac_addr, channel, iface, lmk) {}

  // Destructor of the class
  ~ESP_NOW_Peer_Class() {}

  // Function to register the master peer
  bool add_peer() {
    if (!add()) {
      log_e("Failed to register the broadcast peer");
      return false;
    }
    return true;
  }

  // Function to print the received messages from the master
  void onReceive(const uint8_t *data, size_t len, bool broadcast) {
    Serial.printf("Received a message from master " MACSTR " (%s)\n", MAC2STR(addr()), broadcast ? "broadcast" : "unicast");
    Serial.printf("  Message: %s\n", (char *)data);
  }
};

/* Global Variables */

// List of all the masters. It will be populated when a new master is registered
std::vector<ESP_NOW_Peer_Class> masters;

/* Callbacks */

// Callback called when an unknown peer sends a message
void register_new_master(const esp_now_recv_info_t *info, const uint8_t *data, int len, void *arg) {
  if (memcmp(info->des_addr, ESP_NOW.BROADCAST_ADDR, 6) == 0) {
    Serial.printf("Unknown peer " MACSTR " sent a broadcast message\n", MAC2STR(info->src_addr));
    Serial.println("Registering the peer as a master");

    ESP_NOW_Peer_Class new_master(info->src_addr, ESPNOW_WIFI_CHANNEL, WIFI_IF_STA, NULL);

    masters.push_back(new_master);
    if (!masters.back().add_peer()) {
      Serial.println("Failed to register the new master");
      return;
    }
  } else {
    // The slave will only receive broadcast messages
    log_v("Received a unicast message from " MACSTR, MAC2STR(info->src_addr));
    log_v("Igorning the message");
  }
}

/* Main */

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

  for(int i=0;i<30;i++){
    Serial.println("WiFi");
    delay(1000);
  }//for


//  while (!Serial) {
//    delay(10);
//  }

  // Initialize the Wi-Fi module
  WiFi.mode(WIFI_STA);
  WiFi.setChannel(ESPNOW_WIFI_CHANNEL);
  while (!WiFi.STA.started()) {
    delay(100);
  }

  Serial.println("ESP-NOW Example - Broadcast Slave");
  Serial.println("Wi-Fi parameters:");
  Serial.println("  Mode: STA");
  Serial.println("  MAC Address: " + WiFi.macAddress());
  Serial.printf("  Channel: %d\n", ESPNOW_WIFI_CHANNEL);

  // Initialize the ESP-NOW protocol
  if (!ESP_NOW.begin()) {
    Serial.println("Failed to initialize ESP-NOW");
    Serial.println("Reeboting in 5 seconds...");
    delay(5000);
    ESP.restart();
  }

  // Register the new peer callback
  ESP_NOW.onNewPeer(register_new_master, NULL);

  Serial.println("Setup complete. Waiting for a master to broadcast a message...");
}

void loop() {
  delay(1000);
}



```