Arduino WebClient与MotionDetector运行一段时间后停止故障求助

Hey Daniel, let's figure out why your Arduino setup stops working after running for a while—this is a common pain point with network-connected projects, so let's break down the likely culprits and fixes:

Key Issues in Your Code #

1. Recursive loop() Call (Critical!) #

In your setup() function, you're manually calling loop(); at the end. The Arduino framework automatically runs loop() in an infinite cycle after setup() finishes. Manually calling it creates a recursive loop that will eventually overflow the stack, causing the Arduino to crash. This is almost certainly one of the main reasons your code stops working.

Fix: Remove the loop(); line from setup().

2. Unhandled Network Buffer Overflow #

Your getMovement() and getNoMovement() functions send a GET request but never read the server's response. The EthernetClient has a limited buffer, and if it fills up with unread data, subsequent network operations will fail or hang the device.

Fix: Modify both functions to read the server response and properly clean up connections:

//getMovement - sends a GET request when motion is detected
void getMovement() {
  // Clean up any existing connection first
  if (client.connected()) {
    client.stop();
  }

  if (client.connect(server, 8080)) {
    // Use proper HTTP syntax (add Host header and Connection: close)
    client.println("GET /GetARoomMaven/motion?roomId=1&movement=1 HTTP/1.1");
    client.println("Host: 192.168.50.93");
    client.println("Connection: close");
    client.println();
    Serial.println("Movement Request Sent");

    // Read server response to empty the buffer
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        // Optional: Uncomment to debug response
        // Serial.print(c);
      }
    }
    // Give time for connection to close
    delay(100);
    client.stop();
  } else {
    Serial.println("Movement connection failed");
    client.stop(); // Ensure any partial connection is closed
  }
}

//getNoMovement - sends a GET request when motion had stopped
void getNoMovement() {
  if (client.connected()) {
    client.stop();
  }

  if (client.connect(server, 8080)) {
    client.println("GET /GetARoomMaven/motion?roomId=1&movement=0 HTTP/1.1");
    client.println("Host: 192.168.50.93");
    client.println("Connection: close");
    client.println();
    Serial.println("No Movement Request Sent");

    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
      }
    }
    delay(100);
    client.stop();
  } else {
    Serial.println("No Movement connection failed");
    client.stop();
  }
}

Note: I replaced & with & in the URL—HTML entities aren't needed in HTTP requests.

3. Missing Network Configuration Stability #

Your Ethernet.begin() call only uses the MAC address. Adding your static IP and DNS will make the network connection more reliable, especially after long runs.

Fix: Update the Ethernet initialization in setup():

Ethernet.begin(mac, ip, myDns);

4. No Watchdog Timer for Recovery #

Even with fixes, occasional glitches (like network timeouts or sensor interference) can hang the Arduino. A watchdog timer will automatically restart the device if it stops responding.

Fix: Add watchdog support:

1. Include the library at the top:

#include <avr/wdt.h>

2. Initialize it in setup():

wdt_enable(WDTO_8S); // Restarts Arduino if no "feed" for 8 seconds

3. "Feed" the watchdog in loop() to keep it running:

void loop(){
  wdt_reset(); // Reset watchdog timer at start of loop
  // ... rest of your loop code
}

Additional Hardware Checks #

• Power Supply: Ethernet modules draw significant current. Ensure your Arduino is powered by a stable 5V/2A supply (not just USB from a computer) to avoid brownouts that cause crashes.
• PIR Sensor Wiring: Double-check the sensor's power and ground connections—loose wires can cause intermittent issues that lead to lock-ups.

Try these fixes one by one (start with removing the recursive loop() call, as that's critical) and see if your setup runs reliably long-term!

内容的提问来源于stack exchange，提问作者Daniel H