基于Arduino的电机自动启停系统开发及代码逻辑调试求助

Let's work through why your auto mode isn't updating sensor values or switching the motor correctly, then fix the code step by step.

What's Wrong with the Current Code #

Your existing auto-mode block has two critical flaws that break the intended behavior:

1. It runs only once: Right after setting auto_flag = 1, you execute one sensor check, then immediately set auto_flag = 0—so the auto mode stops before it can monitor changes over time.
2. Duplicate sensor reads: You call readSoil() twice (once in the if condition, once in the print statement), which might give inconsistent readings if moisture shifts between calls.
3. No persistent loop: Auto mode needs to keep running in a loop, checking the sensor repeatedly, until you send an "Auto off" command to disable it.

Corrected Code Implementation #

First, ensure auto_flag is a global variable (so it's accessible to both your SMS command handler and the main loop). Here's the revised logic:

// Global variables (outside any function)
bool auto_flag = false;
const int Maxdryness = /* Insert your threshold value here */;
// Add your pin definitions below (example)
const int motorPin1 = 2;
const int motorPin2 = 3;
const int wetSoil = 4;
const int drySoil = 5;
const int soilSensorPin = A0;

void setup() {
  Serial.begin(9600);
  // Initialize pins
  pinMode(motorPin1, OUTPUT);
  pinMode(motorPin2, OUTPUT);
  pinMode(wetSoil, OUTPUT);
  pinMode(drySoil, OUTPUT);
  // Set initial states
  digitalWrite(motorPin1, LOW);
  digitalWrite(motorPin2, LOW);
  digitalWrite(wetSoil, HIGH);
  digitalWrite(drySoil, LOW);
}

void loop() {
  // Handle incoming SMS commands (adjust this to match your SMS library logic)
  if (hasNewSMS()) {
    String command = getReceivedSMS();
    if (command.equalsIgnoreCase("Auto on")) {
      auto_flag = true;
      send_message("System is now automatic");
    } else if (command.equalsIgnoreCase("Auto off")) {
      auto_flag = false;
      send_message("System is now manual");
      // Clean up motor/LED state when exiting auto mode
      digitalWrite(motorPin1, LOW);
      digitalWrite(motorPin2, LOW);
      digitalWrite(wetSoil, HIGH);
      digitalWrite(drySoil, LOW);
    } else if (command.equalsIgnoreCase("Motor on")) {
      auto_flag = false; // Disable auto mode for manual control
      digitalWrite(motorPin1, HIGH);
      digitalWrite(motorPin2, LOW);
      send_message("Motor turned on manually");
    } else if (command.equalsIgnoreCase("Motor off")) {
      auto_flag = false;
      digitalWrite(motorPin1, LOW);
      digitalWrite(motorPin2, LOW);
      send_message("Motor turned off manually");
    }
  }

  // Auto mode logic: runs continuously while auto_flag is true
  if (auto_flag) {
    // Read sensor once and store the value to avoid inconsistent readings
    int sensorValue = readSoil();
    
    Serial.print("Soil Moisture = ");
    Serial.println(sensorValue);

    // Check moisture threshold and adjust motor/LEDs
    if (sensorValue >= Maxdryness) {
      Serial.println("Soil is good.");
      digitalWrite(wetSoil, HIGH);
      digitalWrite(drySoil, LOW);
      digitalWrite(motorPin1, LOW);
      digitalWrite(motorPin2, LOW);
    } else {
      Serial.println("Low Soil Moisture detected.");
      digitalWrite(wetSoil, LOW);
      digitalWrite(drySoil, HIGH);
      digitalWrite(motorPin1, HIGH);
      digitalWrite(motorPin2, LOW);
    }

    delay(1000); // Adjust delay for desired check frequency (1 second here)
  }

  // Add any other background tasks or manual mode logic here
}

// Your existing sensor reading function (adjust to match your hardware)
int readSoil() {
  return analogRead(soilSensorPin); // Example for analog soil sensor
}

Key Fixes Explained #

• Persistent auto mode: The auto logic runs in the main loop() and keeps checking the sensor as long as auto_flag is true. It only stops when you send an "Auto off" command.
• Single sensor read: We store the sensor value in a variable once per loop iteration, so the condition check and print statement use the exact same reading.
• Clear mode separation: Manual commands (Motor on/off) automatically disable auto mode to prevent conflicts, and exiting auto mode resets the motor/LEDs to a safe state.
• Real-time updates: Every loop iteration refreshes the sensor value and adjusts the motor based on current moisture, so it reacts immediately when the soil switches between wet and dry.

Additional Tips #

• Add sensor debouncing: If your readings are noisy, average 3-5 consecutive reads to avoid false motor triggers.
• Use non-blocking delays: Replace delay() with millis() if you need the system to handle incoming SMS more responsively (no more missed commands during delays).
• Verify Maxdryness: Double-check that your threshold matches your sensor's behavior (most analog soil sensors return higher values for drier soil).

内容的提问来源于stack exchange，提问作者Cynthia Aranda