Formation Flight

Overview

Formation flight is a cutting-edge application of drone technology. In this project, you will learn how to use the ESP-NOW protocol to achieve simple formation flight between two drones.

What You’ll Learn

• ESP-NOW communication protocol
• Multi-drone coordination
• Formation control basics
• Leader-follower strategy

Materials Needed

Step 1: Understand ESP-NOW

ESP-NOW is a low-latency, low-power point-to-point communication protocol suitable for communication between drones.

Step 2: Configure ESP-NOW

Drone A (Leader) - Send Position

void send_position_to_follower() {
    float x, y, z;
    estimatorGetPosition(&x, &y, &z);
    
    // Build message
    uint8_t message[12];
    memcpy(message, &x, 4);
    memcpy(message + 4, &y, 4);
    memcpy(message + 8, &z, 4);
    
    // Send message
    esp_now_send(follower_mac, message, sizeof(message));
}

Drone B (Follower) - Receive Position

void on_data_recv(const uint8_t *mac_addr, const uint8_t *data, int data_len) {
    if (data_len == 12) {
        float leader_x, leader_y, leader_z;
        memcpy(&leader_x, data, 4);
        memcpy(&leader_y, data + 4, 4);
        memcpy(&leader_z, data + 8, 4);
        
        // Follow the leader
        float follower_x = leader_x - 1.0; // Keep 1 meter distance
        float follower_y = leader_y;
        float follower_z = leader_z;
        
        commanderSetPositionSetpoint(follower_x, follower_y, follower_z, 0);
    }
}

Step 3: Initialize ESP-NOW

void espnow_init() {
    // Initialize ESP-NOW
    esp_now_init();
    
    // Register callback functions
    esp_now_register_send_cb(on_data_sent);
    esp_now_register_recv_cb(on_data_recv);
    
    // Add peer
    esp_now_peer_info_t peer_info = {};
    memcpy(peer_info.peer_addr, peer_mac, 6);
    peer_info.channel = 0;
    peer_info.encrypt = false;
    esp_now_add_peer(&peer_info);
}

Step 4: Compile and Flash

1. Compile and flash Drone A’s code to the leader drone
2. Compile and flash Drone B’s code to the follower drone
3. Power on both drones and test

Step 5: Test Formation Flight

1. Place both drones on the ground
2. Power on Drone B first, then Drone A
3. Take off with Drone A
4. Observe if Drone B follows Drone A

Troubleshooting

Cannot communicate

• Check MAC addresses
• Confirm ESP-NOW is initialized

Follower doesn’t follow

• Check position data
• Adjust following parameters

Achievement

Congratulations! You have completed all beginner projects and mastered the basics of drone development!

Next Steps

You are now ready to enter the intermediate level and learn more advanced programming and debugging skills.

Enter Intermediate Level →