ZigBee Wireless Communication for Microcontrollers: Building Low-Power Wireless Sensor Networks

Wireless communication is becoming increasingly important in industrial automation and the Internet of Things (IoT). Today, we will discuss ZigBee wireless communication technology based on microcontrollers. ZigBee acts like a low-power “wireless relay station,” making it particularly suitable for sensor data collection and remote control applications.

1. What is ZigBee?

ZigBee can be understood as a “power-saving version of WiFi.” It typically has a transmission range of up to 100 meters and a relatively low transmission speed (250 kbps), but it is extremely energy-efficient. For example, a ZigBee module can operate for several months on a single AA battery. This characteristic makes it very suitable for battery-powered remote sensors.

2. Hardware Connections

The main modules used are:

• Microcontroller (taking STM32F103 as an example)
• ZigBee module (such as CC2530/CC2538)
• Power module (3.3V voltage regulator)

Key connection points:

1. The ZigBee module connects to the microcontroller via a serial port (UART).
2. Pay attention to level matching; most ZigBee modules operate and communicate at 3.3V.
3. The antenna position should be arranged reasonably to avoid metal obstructions.

3. Program Implementation

c code

// Serial port initialization configuration
void UART_Init(void)
{
    // Baud rate 115200, 8 data bits, 1 stop bit
    USART_InitStructure.USART_BaudRate = 115200;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_Init(USART1, &USART_InitStructure);
}

// Send data packet
void SendZigbeeData(uint8_t *data, uint16_t len)
{
    uint16_t i;
    for(i = 0; i < len; i++)
    {
        while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
        USART_SendData(USART1, data[i]);
    }
}

4. Network Formation

ZigBee networks have three roles:

1. Coordinator: the “manager” of the network, responsible for establishing and managing the entire network.
2. Router: the “relay station,” responsible for forwarding data.
3. End device: a regular member that can sleep to save power.

Steps to set up:

1. First, set up a coordinator and wait for it to establish the network.
2. Routers can join the network to extend coverage.
3. End devices connect to the nearest router or coordinator.

5. Common Issues and Solutions

1. Insufficient communication distance

• Check antenna installation.
• Add router nodes.
• Adjust transmission power.

1. High power consumption

• Use sleep mode.
• Optimize wake-up cycles.
• Reduce data transmission frequency.

1. Severe packet loss

• Check serial port baud rate settings.
• Add data verification mechanisms.
• Avoid sources of interference on the same frequency.

6. Practical Application Case

Greenhouse monitoring:

• Multiple sensor nodes collect temperature and humidity data.
• Data is transmitted to the control center via the ZigBee network.
• Automatically control ventilation and heating equipment.
• Battery-powered for easy maintenance.

Debugging experience:

1. Always prepare a logic analyzer to capture communication data.
2. Ensure the correct firmware is programmed for the module on first use.
3. Start debugging with point-to-point communication, and once confirmed reliable, proceed to network formation.

Important performance indicators:

• Sleep current: < 1uA
• Communication distance: 100m outdoors, 30m indoors
• Network capacity: up to 250 nodes in one network
• Transmission rate: 250kbps

Hands-on practice suggestions:

1. Set up point-to-point communication between two nodes.
2. Test communication distance at different transmission power levels.
3. Implement simple sensor data collection and display.
4. Attempt to build a multi-node star network.

Safety reminders:

1. Be cautious of short circuits; power supply to the module must strictly follow specifications.
2. Protect exposed parts of the antenna.
3. Do not exceed the module specifications for power settings.
4. Use encryption features to protect data security.