Arduino-C++ Bool 不会从 False 变为 True

Question

我目前正在尝试制作一个 NFC 门锁，并且我正在尝试制作它以便在门被锁上时它知道并会使用正确的 NFC 卡解锁门，反之亦然。我创建了 bool locked 并使其 = false。当我打开门时，我已经做到了，它会将 bool locked 从 false 更改为 true，尽管这不起作用并且 NFC 卡每次都会继续锁门。

NFC卡读取区域：


    if ( ! mfrc522.PICC_IsNewCardPresent())
        return;

    // Select one of the cards
    if ( ! mfrc522.PICC_ReadCardSerial())
        return;

    // Show some details of the PICC (that is: the tag/card)
    bool locked = false;
    if(locked == false)
    {
    Serial.print(F("Card UID:"));
    dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
    byte valid[4] = { 0xEB, 0xA6, 0xE9, 0x21 };
    if (memcmp(valid, mfrc522.uid.uidByte, mfrc522.uid.size) == 0) {
        Serial.print("Door Locked"); 
        int motorPin = 3;
        digitalWrite(motorPin, HIGH); // turns the motor ON
        delay(5000);
        digitalWrite(motorPin, LOW); // turns the motor OFF
        bool locked = true;
    }}
    if(locked == true)
    {
    Serial.print(F("Card UID:"));
    dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
    byte valid[4] = { 0xEB, 0xA6, 0xE9, 0x21 };
    if (memcmp(valid, mfrc522.uid.uidByte, mfrc522.uid.size) == 0) {
        Serial.print("Door Unlocked");
        int motorPin = 3;
        digitalWrite(motorPin, HIGH); // turns the motor ON
        delay(5000);
        digitalWrite(motorPin, LOW); // turns the motor OFF
        bool locked = false;
    }}
    Serial.println();
    Serial.print(F("PICC type: "));
    MFRC522::PICC_Type piccType = mfrc522.PICC_GetType(mfrc522.uid.sak);
    Serial.println(mfrc522.PICC_GetTypeName(piccType));

完整代码：

#include <SoftwareSerial.h>
#include <ArduinoBlue.h>
#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN         9           // Configurable, see typical pin layout above
#define SS_PIN          10          // Configurable, see typical pin layout above



const unsigned long BAUD_RATE = 9600;

// The bluetooth tx and rx pins must be supported by software serial.
// Visit https://www.arduino.cc/en/Reference/SoftwareSerial for unsupported pins.
// Bluetooth TX -> Arduino D8
const int BLUETOOTH_TX = 8;
// Bluetooth RX -> Arduino D7
const int BLUETOOTH_RX = 7;

int prevThrottle = 49;
int prevSteering = 49;
int throttle, steering, sliderVal, button, sliderId;

SoftwareSerial bluetooth(BLUETOOTH_TX, BLUETOOTH_RX);
ArduinoBlue phone(bluetooth); // pass reference of bluetooth object to ArduinoBlue constructor

MFRC522 mfrc522(SS_PIN, RST_PIN);   // Create MFRC522 instance.

// Number of known default keys (hard-coded)
// NOTE: Synchronize the NR_KNOWN_KEYS define with the defaultKeys[] array
#define NR_KNOWN_KEYS   8
// Known keys, see: https://code.google.com/p/mfcuk/wiki/MifareClassicDefaultKeys
byte knownKeys[NR_KNOWN_KEYS][MFRC522::MF_KEY_SIZE] =  {
    {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, // FF FF FF FF FF FF = factory default
    {0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5}, // A0 A1 A2 A3 A4 A5
    {0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5}, // B0 B1 B2 B3 B4 B5
    {0x4d, 0x3a, 0x99, 0xc3, 0x51, 0xdd}, // 4D 3A 99 C3 51 DD
    {0x1a, 0x98, 0x2c, 0x7e, 0x45, 0x9a}, // 1A 98 2C 7E 45 9A
    {0xd3, 0xf7, 0xd3, 0xf7, 0xd3, 0xf7}, // D3 F7 D3 F7 D3 F7
    {0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}, // AA BB CC DD EE FF
    {0x00, 0x00, 0x00, 0x00, 0x00, 0x00}  // 00 00 00 00 00 00
};


// Setup code runs once after program starts.
void setup() {
    // Start serial communications.
    // The baud rate must be the same for both the serial and the bluetooth.
    SPI.begin(); 
    Serial.begin(BAUD_RATE);
    while (!Serial);            // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)
    mfrc522.PCD_Init();         // Init MFRC522 card
    Serial.println(F("Try the most used default keys to print block 0 of a MIFARE PICC."));
    bluetooth.begin(BAUD_RATE);
    delay(100);

    Serial.println("setup complete");
}

void dump_byte_array(byte *buffer, byte bufferSize) {
    for (byte i = 0; i < bufferSize; i++) {
        Serial.print(buffer[i] < 0x10 ? " 0" : " ");
        Serial.print(buffer[i], HEX);
    }
}

bool try_key(MFRC522::MIFARE_Key *key)
{
    bool result = false;
    byte buffer[18];
    byte block = 0;
    MFRC522::StatusCode status;

    // Serial.println(F("Authenticating using key A..."));
    status = mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, block, key, &(mfrc522.uid));
    if (status != MFRC522::STATUS_OK) {
        // Serial.print(F("PCD_Authenticate() failed: "));
        // Serial.println(mfrc522.GetStatusCodeName(status));
        return false;
    }

    // Read block
    byte byteCount = sizeof(buffer);
    status = mfrc522.MIFARE_Read(block, buffer, &byteCount);
    if (status != MFRC522::STATUS_OK) {
        // Serial.print(F("MIFARE_Read() failed: "));
        // Serial.println(mfrc522.GetStatusCodeName(status));
    }
    else {
        // Successful read
        result = true;
        Serial.print(F("Success with key:"));
        dump_byte_array((*key).keyByte, MFRC522::MF_KEY_SIZE);
        Serial.println();
        // Dump block data
        Serial.print(F("Block ")); Serial.print(block); Serial.print(F(":"));
        dump_byte_array(buffer, 16);
        Serial.println();
    }
    Serial.println();

    mfrc522.PICC_HaltA();       // Halt PICC
    mfrc522.PCD_StopCrypto1();  // Stop encryption on PCD
    return result;
}

void loop() {

    button = phone.getButton();

    // Returns the text data sent from the phone.
    // After it returns the latest data, empty string "" is sent in subsequent.
    // calls until text data is sent again.
    String str = phone.getText();

    // Display button data whenever its pressed.
    if (button == 1) {
        Serial.print("Door Locked");
    }

        // Display button data whenever its pressed.
    if (button == 0) {
        Serial.print("Door Unlocked");
        int motorPin = 3;
        digitalWrite(motorPin, HIGH); // turns the motor ON
        delay(5000);
        digitalWrite(motorPin, LOW); // turns the motor OFF



    }


    // Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.

    if ( ! mfrc522.PICC_IsNewCardPresent())
        return;

    // Select one of the cards
    if ( ! mfrc522.PICC_ReadCardSerial())
        return;

    // Show some details of the PICC (that is: the tag/card)
    bool locked = false;
    if(locked == false)
    {
    Serial.print(F("Card UID:"));
    dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
    byte valid[4] = { 0xEB, 0xA6, 0xE9, 0x21 };
    if (memcmp(valid, mfrc522.uid.uidByte, mfrc522.uid.size) == 0) {
        Serial.print("Door Locked"); 
        int motorPin = 3;
        digitalWrite(motorPin, HIGH); // turns the motor ON
        delay(5000);
        digitalWrite(motorPin, LOW); // turns the motor OFF
        bool locked = true;
    }}
    if(locked == true)
    {
    Serial.print(F("Card UID:"));
    dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
    byte valid[4] = { 0xEB, 0xA6, 0xE9, 0x21 };
    if (memcmp(valid, mfrc522.uid.uidByte, mfrc522.uid.size) == 0) {
        Serial.print("Door Unlocked");
        int motorPin = 3;
        digitalWrite(motorPin, HIGH); // turns the motor ON
        delay(5000);
        digitalWrite(motorPin, LOW); // turns the motor OFF
        bool locked = false;
    }}
    Serial.println();
    Serial.print(F("PICC type: "));
    MFRC522::PICC_Type piccType = mfrc522.PICC_GetType(mfrc522.uid.sak);
    Serial.println(mfrc522.PICC_GetTypeName(piccType));

    // Try the known default keys
    MFRC522::MIFARE_Key key;
    for (byte k = 0; k < NR_KNOWN_KEYS; k++) {
        // Copy the known key into the MIFARE_Key structure
        for (byte i = 0; i < MFRC522::MF_KEY_SIZE; i++) {
            key.keyByte[i] = knownKeys[k][i];
        }
        // Try the key
        if (try_key(&key)) {
            // Found and reported on the key and block,
            // no need to try other keys for this PICC
            break;
        }

        // http://arduino.stackexchange.com/a/14316
        if ( ! mfrc522.PICC_IsNewCardPresent())
            break;
        if ( ! mfrc522.PICC_ReadCardSerial())
            break;
    }
}

Answer 1

在您的 if 语句范围内，您创建了另一个局部变量 bool locked 并且您不重新分配用于检查当前状态的那个。

因此，无需深入查看其余代码，您需要为 locked 分配正确的值，而不是定义另一个锁定变量：

locked = false;

而不是

bool locked = false;

澄清：

int a = 0;

if (1)
{
    int a = 42; // this is not 'a' from above
    std::cout << "value of a: " << a << "\n";
} // here ends the lifetime of the inner 'a'

std::cout << "value of a: " << a << "\n";

输出：

value of a: 42
value of a: 0

Arduino-C++ Bool 不会从 False 变为 True

Arduino-C++ Bool Not Changing From False To True

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