esp8266 espnow代码

以下是 ESP8266 使用 ESP-NOW 的示例代码：

#include <ESP8266WiFi.h>
#include <espnow.h>

#define CHANNEL 1
#define PRINTSCANRESULTS 0
#define WIFI_CHANNEL_SWITCH_INTERVAL 5000

// Replace with your network credentials
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

// Send and receive structure
typedef struct struct_message {
  int id;
  float temperature;
  float humidity;
} struct_message;

// Create a struct_message called myData
struct_message myData;

// MAC address of the receiver ESP8266
uint8_t broadcastAddress[] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

// callback function when data is received
void OnDataRecv(uint8_t *mac_addr, uint8_t *incomingData, uint8_t len) {
  memcpy(&myData, incomingData, sizeof(myData));
  Serial.print("Bytes received: ");
  Serial.println(len);
  Serial.print("Received packet from: ");
  Serial.println(mac_addr);
  Serial.print("Message ID: ");
  Serial.println(myData.id);
  Serial.print("Temperature: ");
  Serial.println(myData.temperature);
  Serial.print("Humidity: ");
  Serial.println(myData.humidity);
}

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

  // Set device as a Wi-Fi Station
  WiFi.mode(WIFI_STA);

  // Init ESP-NOW
  if (esp_now_init() != 0) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }

  // Register peer
  esp_now_peer_info_t peerInfo;
  memcpy(peerInfo.peer_addr, broadcastAddress, 6);
  peerInfo.channel = CHANNEL;
  peerInfo.encrypt = false;

  // Add peer
  if (esp_now_add_peer(&peerInfo) != 0) {
    Serial.println("Failed to add peer");
    return;
  }

  // Register for a callback function when data is received
  esp_now_set_data_recv_cb(OnDataRecv);

  // Connect to Wi-Fi network
  WiFi.begin(ssid, password);
  Serial.println("Connecting to Wi-Fi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  myData.id = 1;
  myData.temperature = 25.0;
  myData.humidity = 50.0;

  // Send message via ESP-NOW
  esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
  if (result == ESP_OK) {
    Serial.println("Sent with success");
  }
  else if (result == ESP_ERR_ESPNOW_NOT_INIT) {
    Serial.println("ESPNOW not Init.");
  }
  else if (result == ESP_ERR_ESPNOW_ARG) {
    Serial.println("Invalid Argument");
  }
  else if (result == ESP_ERR_ESPNOW_INTERNAL) {
    Serial.println("Internal Error");
  }
  else if (result == ESP_ERR_ESPNOW_NO_MEM) {
    Serial.println("ESP_ERR_ESPNOW_NO_MEM");
  }
  else if (result == ESP_ERR_ESPNOW_NOT_FOUND) {
    Serial.println("Peer not found.");
  }
  else {
    Serial.println("Not sure what happened");
  }

  delay(1000);
}

在这个例子中，我们定义了一个用于发送和接收的结构体 `struct_message`，该结构体包含三个变量：`id`、`temperature` 和 `humidity`。在 `setup` 函数中，我们初始化了 ESP-NOW，并注册了一个回调函数 `OnDataRecv`，以便在接收到数据时能够处理它。在 `loop` 函数中，我们创建了一个名为 `myData` 的 `struct_message` 结构体，并将其发送到广播地址。在发送数据后，我们等待 1 秒后重复此过程。

请注意，如果您使用的是 ESP8266 的 NodeMCU 开发板，则需要将 `tx_pin` 和 `rx_pin` 设为 `2` 和 `3`，而不是默认的 `Arduino` 引脚。可以使用以下代码将它们设置为正确的引脚：

#define RX_PIN 3
#define TX_PIN 2

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

  pinMode(RX_PIN, INPUT);
  pinMode(TX_PIN, OUTPUT);
  Serial.swap();  // swap RX/TX pins
  Serial.begin(115200);
  ...
}

希望这能帮助您开始使用 ESP-NOW。