Multi-Drone Communication

Overview

Multi-drone coordination is a cutting-edge direction in drone technology. In this project, you will learn how to achieve simple communication between two drones and understand wireless communication principles.

What You’ll Learn

• Wireless communication principles
• ESP-NOW protocol
• Multi-drone coordination strategies
• Leader-follower mode

Materials Needed

Item	Quantity	Notes
Two Fully Assembled Drones	2	Drone A and Drone B
Computer	1	With VS Code + ESP-IDF environment
USB Cables	2	For programming

Step 1: Understand Wireless Communication

ESP32 supports Wi-Fi and ESP-NOW communication protocols.

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

Step 2: Configure ESP-NOW

In the components/drivers/general/wifi directory, understand ESP-NOW configuration and usage methods.

Configure ESP-NOW separately for Drone A and Drone B, setting communication addresses.

Step 3: Write Communication Code

Drone A Send Code:

void sendPositionToFollower() {
    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 Receive Code:

void onDataRecv(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 4: Compile, Flash and Test

1. Compile Drone A and Drone B code separately
2. Flash to corresponding drones
3. Power on and test, observe if Drone B can follow Drone A

Troubleshooting

Cannot communicate

• Check if MAC addresses are correct
• Confirm ESP-NOW is initialized

Follower not following

• Check position data
• Adjust following parameters

Achievement

Congratulations! You have completed all intermediate projects and mastered drone programming and debugging skills!

Next Steps

You are now ready to enter the advanced level and learn more complex algorithms and system integration.