Supported devices	ESP8266	ESP32	ESP32-S2	ESP32-S3	ESP32-C2	ESP32-C3	ESP32-C6

ESP32 ESP-IDF and ESP8266 RTOS SDK component for ESP-NOW based mesh network

Tested on

1. ESP8266 RTOS_SDK v3.4
2. ESP32 ESP-IDF v5.2

Features

1. The maximum size of transmitted data is up to 218 bytes. For details see Attention.
2. Support of any data types.
3. All nodes are not visible to the network scanner.
4. Not required a pre-pairings for data transfer.
5. Broadcast or unicast data transmissions.
6. There are no periodic/synchronous messages on the network. All devices are in "silent mode" and do not "hum" into the air.
7. Each node has its own independent routing table, updated only as needed.
8. Each node will receive/send a message if it "sees" at least one device on the network.
9. The number of devices on the network and the area of use is not limited.
10. Possibility uses WiFi AP or STA modes at the same time with ESP-NOW. For details see Attention.

Attention

1. The definition of ZH_NETWORK_MAX_MESSAGE_SIZE in the zh_network.h can be changed between 1 and 218. Smaller size - higher transmission speed. All devices on the network must have the same ZH_NETWORK_MAX_MESSAGE_SIZE.
2. For correct work at ESP-NOW + STA mode your WiFi router must be set on channel 1.
3. The ZHNetwork and the zh_network are incompatible.

Testing

1. Program 2 receivers and 1 transmitter (specify the MAC of the 1st receiver in the code).
2. Connect the 1st receiver to the computer. Switch on serial port monitor. Turn transmitter on. Receiver will start receiving data.
3. Move transmitter as far away from receiver as possible until receiver is able to receive data (shield module if necessary).
4. Turn on the 2nd receiver and place it between the 1st receiver and transmitter (preferably in the middle). The 1st receiver will resume data reception (with relaying through the 2nd receiver). P.S. You can use a transmitter instead of the 2nd receiver - makes no difference.

Initial settings

1. network_id - A unique ID for the mesh network. The ID must be the same for all nodes in the network.
2. task_priority - Task priority for the messages processing. It is not recommended to change this value.
3. stack_size - Task stask size for the messages processing. It is not recommended to change this value.
4. queue_size - Size of messages processing queue. It is not recommended to set a value lower than 32.
5. max_waiting_time - Maximum time to wait a response message from a target node. In milliseconds. If a response message from the target node is not received within this time, the status of the sent message will be "sent fail".
6. id_vector_size - Maximum size of unique ID of received messages. If the size is exceeded, the first value will be deleted. Minimum recommended value: number of planned nodes in the network + 10%.
7. route_vector_size - The maximum size of the routing table. If the size is exceeded, the first route will be deleted. Minimum recommended value: number of planned nodes in the network + 10%.
8. wifi_interface - WiFi interface used for ESP-NOW data transmission.

Using

In an existing project, run the following command to install the component:

cd ../your_project/components
git clone http://git.zh.com.ru/alexey.zholtikov/zh_vector.git
git clone http://git.zh.com.ru/alexey.zholtikov/zh_network.git

In the application, add the component:

#include "zh_network.h"

Example

Sending and receiving messages:

#include "nvs_flash.h"
#include "esp_netif.h"
#include "zh_network.h"

#define MAC2STR(a) (a)[0], (a)[1], (a)[2], (a)[3], (a)[4], (a)[5]

void zh_network_event_handler(void *arg, esp_event_base_t event_base, int32_t event_id, void *event_data);

uint8_t target[6] = {0x58, 0xBF, 0x25, 0x18, 0xC8, 0x04};

typedef struct example_message_t
{
    char char_value[30];
    int int_value;
    float float_value;
    bool bool_value;
} example_message_t;

void app_main(void)
{
    nvs_flash_init();
    esp_netif_init();
    esp_event_loop_create_default();
    wifi_init_config_t wifi_init_config = WIFI_INIT_CONFIG_DEFAULT();
    esp_wifi_init(&wifi_init_config);
    esp_wifi_set_mode(WIFI_MODE_STA);
    esp_wifi_start();
    esp_wifi_set_max_tx_power(8); // Power reduction is for example and testing purposes only. Do not use in your own programs!
    zh_network_init_config_t zh_network_init_config = ZH_NETWORK_INIT_CONFIG_DEFAULT();
    zh_network_init_config.id_vector_size = 150; // Just for an example of how to change the default values.
    zh_network_init(&zh_network_init_config);
#ifdef CONFIG_IDF_TARGET_ESP8266
    esp_event_handler_register(ZH_NETWORK, ESP_EVENT_ANY_ID, &zh_network_event_handler, NULL);
#else
    esp_event_handler_instance_register(ZH_NETWORK, ESP_EVENT_ANY_ID, &zh_network_event_handler, NULL, NULL);
#endif
    example_message_t send_message;
    strcpy(send_message.char_value, "THIS IS A CHAR");
    send_message.float_value = 1.234;
    send_message.bool_value = false;
    for (;;)
    {
        send_message.int_value = esp_random();
        zh_network_send(NULL, (uint8_t *)&send_message, sizeof(send_message));
        vTaskDelay(5000 / portTICK_PERIOD_MS);
        zh_network_send(target, (uint8_t *)&send_message, sizeof(send_message));
        vTaskDelay(5000 / portTICK_PERIOD_MS);
    }
}

void zh_network_event_handler(void *arg, esp_event_base_t event_base, int32_t event_id, void *event_data)
{
    switch (event_id)
    {
    case ZH_NETWORK_ON_RECV_EVENT:;
        zh_network_event_on_recv_t *recv_data = event_data;
        printf("Message from MAC %02X:%02X:%02X:%02X:%02X:%02X is received. Data lenght %d bytes.\n", MAC2STR(recv_data->mac_addr), recv_data->data_len);
        example_message_t *recv_message = (example_message_t *)recv_data->data;
        printf("Char %s\n", recv_message->char_value);
        printf("Int %d\n", recv_message->int_value);
        printf("Float %f\n", recv_message->float_value);
        printf("Bool %d\n", recv_message->bool_value);
        free(recv_data->data); // Do not delete to avoid memory leaks!
        break;
    case ZH_NETWORK_ON_SEND_EVENT:;
        zh_network_event_on_send_t *send_data = event_data;
        if (send_data->status == ZH_NETWORK_SEND_SUCCESS)
        {
            printf("Message to MAC %02X:%02X:%02X:%02X:%02X:%02X sent success.\n", MAC2STR(send_data->mac_addr));
        }
        else
        {
            printf("Message to MAC %02X:%02X:%02X:%02X:%02X:%02X sent fail.\n", MAC2STR(send_data->mac_addr));
        }
        break;
    default:
        break;
    }
}

Thanks to Marton Larrosa for participating in the testing.

Any feedback will be gladly accepted.