box.c

#include <stdbool.h>
#include <AnalogKeypad.h>
#include <Servo.h>

// Arduino Pin Assignments
#define PIN_KEYS  A0
#define PIN_SERVO 9
#define PIN_LED   13

// Servo Configurations
#define SRV_DELAY   5000
#define SRV_PASSIVE 10      // 10 degree angle passive (0 fails)
#define SRV_ACTIVE  20      // 20 degree angle active


AnalogKeypad keyPad = AnalogKeypad(PIN_KEYS);
Servo srvLatch;

int valid[] = {
    (int)KEY_3,
    (int)KEY_2,
    (int)KEY_5,
    (int)KEY_2,
    (int)KEY_0,
    (int)KEY_1,
    (int)KEY_6
};

int pointer = 0;
bool keyReset = true;


// Determine the length of the password based on byte division
int passLength = (sizeof(valid) / sizeof(int)) - 1;


/**
 * Setup function called prior to main loop.
 */
void setup() {
    pinMode(PIN_LED, OUTPUT);
    
    Serial.begin(115200);
    
    // Initialize the keypad module
    keyPad.init();
    
    // Reset our Servo to the locked state
    srvLatch.attach(PIN_SERVO);
    srvLatch.write(SRV_PASSIVE);
}


/**
 * Main loop function.
 */
void loop() {
    int input = keyPad.readKey();
    
    // Skip out early if we're not pressing anything
    if (input == KEY_NONE) {
        keyReset = true;
        return;
    }
    
    // Parse a keypress if we've had a reset
    if (keyReset) {
        // Blink the LED
        digitalWrite(PIN_LED, HIGH);
        delay(250);
        digitalWrite(PIN_LED, LOW);
        
        // Check if this entry of the passcode is correct
        if (valid[pointer] == (int)key) {
            pointer++;
            
            Serial.print("Key ");
            Serial.print(pointer);
            Serial.print(" of ");
            Serial.print(passLength);
            Serial.print(" == ");
            Serial.println(key);
            
            // Valid password entered, open the latch temporarily
            if (pointer >= passLength) {
                Serial.println("***VALID***");
                srvLatch.write(SRV_ACTIVE);
                delay(SRV_DELAY);
                srvLatch.write(SRV_PASSIVE);
                pointer = 0;
            }
            
        } else {
            Serial.println("Invalid key, resetting.");
            pointer = 0;
        }
        
        // Make sure there is a KEY_NONE before we process again
        keyReset = false;
    }
}