> For the complete documentation index, see [llms.txt](https://guides.mccaskeyrobotics.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guides.mccaskeyrobotics.org/arduino/passcode-protected-tollbooth.md). # Passcode Protected Tollbooth ### Introduction Video: {% embed url="" %} ### Overview: When you pull up to a many buildings, the gate only opens if you know the passcode. In this project you will use a 4 by 4 keypad to feed Arduino information. Arduino will keep track of that information and decide whether or not it matches the pre-determined passcode. If it does, it will send signal to a motor driver board and open or close the gate. If not, it will ask for new information. ![](/files/ZXtPoGOq7SjqVhviPyAg)![](/files/3FCYPz5Rutbq8Z8P9Ihs) ### Parts: \- 1 L298N Motor Driver Board \- 1 Arduino Uno \- 1 Tollbooth Setup \- 1 4 by 4 keypad \- 1 9V Battery \- Assorted Wire ### Wiring: ![](/files/4UoYDB2WweF4ex4LUInu) ![](/files/u69shtxMSYMIyZVhrevg) ### Code: ```cpp #include //library to simplify accepting input from the keypad const byte ROWS = 4; //four rows const byte COLS = 4; //four columns //define the cymbols on the buttons of the keypads char hexaKeys[ROWS][COLS] = { {'1', '2', '3', 'A'}, {'4', '5', '6', 'B'}, {'7', '8', '9', 'C'}, {'*', '0', '#', 'D'} }; byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad #define Password_Length 7 char Data[Password_Length]; // 6 is the number of chars it can hold + the null char = 7 char o_master[Password_Length] = "123456"; char c_master[Password_Length] = "654321"; byte data_count = 0, master_count = 0; bool Pass_is_good; // declare the pins for the open/close limit switches int olim = 11; int clim = 10; //declare the pincs for the open/close gate enable pins going to the L298 driver int ogate = 13; int cgate = 12; //initialize an instance of class NewKeypad Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); void setup() { Serial.begin(9600); //initialize gate control pins as inputs/outputs pinMode(olim, INPUT_PULLUP); pinMode(clim, INPUT_PULLUP); pinMode(ogate, OUTPUT); pinMode(cgate, OUTPUT); initialize(); } // the main loop of the program void loop() { char customKey = customKeypad.getKey(); //only runs when it receives data from the kaypad if (customKey) { Serial.print(customKey); //print the current key entry to the serial monitor Data[data_count] = customKey; //place the key entry in the data array data_count ++; // move to the next spot in the array // wait till there are 6 positions filled in the array if (data_count == Password_Length - 1) { //compare the array to the open password, if it's a match, open the gate if (!strcmp(Data, o_master)) { Serial.println(""); Serial.println("Correct, you may enter"); open_gate(); clear_data(); initialize(); } //compare the array to the close password, if it's a match, close the gate else if (!strcmp(Data, c_master)) { Serial.println(""); Serial.println("Correct, the gate is closing"); close_gate(); clear_data(); initialize(); } //if the password doesn't match either, ask the user to try again. else { Serial.println(""); Serial.println("Incorect. Please try again"); clear_data(); initialize(); } } } } //determines where the gate is at and prompts the user to enter a password //if gate isn't at top or bottom, it takes it to the bottom and prompts user to enter password void initialize() { int close_value = digitalRead(clim); int open_value = digitalRead(olim); if (close_value == LOW ) { Serial.println("Please enterthe 6 digit open password"); return; } else if (open_value == LOW) { Serial.println("Please enter the 6 digit close password"); return; } else { while (digitalRead(clim) == HIGH) { digitalWrite(cgate, HIGH); digitalWrite(ogate, LOW); } digitalWrite(cgate, LOW); digitalWrite(ogate, LOW); delay(100); Serial.println("Please enter the 6 digit open password"); return; } } //clears the list of numbers in the keypad array void clear_data() { while (data_count != 0) { Data[data_count--] = 0; } return; } // runs the motor in the open direction while the open limit switch is not pressed, //then turns off the motors before going back to main program void open_gate() { while (digitalRead(olim) == HIGH) { digitalWrite(ogate, HIGH); digitalWrite(cgate, LOW); } digitalWrite(ogate, LOW); digitalWrite(cgate, LOW); delay(100); return; } // runs motor in close direction while the close limit switch is not pressed, //then turns off the motors before going back to main program void close_gate() { while (digitalRead(clim) == HIGH) { digitalWrite(ogate, LOW); digitalWrite(cgate, HIGH); } digitalWrite(ogate, LOW); digitalWrite(cgate, LOW); delay(100); return; } ``` --- # Agent Instructions This documentation is published with GitBook. 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