Published June 13, 2019

Arduino Lock Box

A quick build for an Arduino Uno that uses a countdown timer to open a servo motor gate in order to use it as a lock.

BeginnerFull instructions provided21,285

Things used in this project

Hardware components

Jumper wires (generic)

Resistor 10k ohm

Resistor 220 ohm

Tactile Switch, Top Actuated

SG90 Micro-servo motor

Liquid Crystal Display

(Generic one that comes with Arduino Starter Kit)

Single Turn Potentiometer- 10k ohms

(Whatever the Generic Potentiometer in the Arduino Kit is)

Arduino UNO

Breadboard (generic)

Story

NOTE:

If you are having trouble with making this project work properly please view this forum link: https://forum.arduino.cc/index.php?topic=621641.0

Apologies to those who have had issues with this. I will update the project as soon as I have time to do so!

So, Why Build This?

This invention is deigned to be a “lock box” with a timer. Once the timer has counted down to zero it sends a signal to rotate the servo motor 90 degrees to unlock the hatch on the box it is installed in. There are four push buttons, if you hold the first to the left, it will bring you into settings. Here you can use the second button from the left to toggle between hours, minutes, and seconds. Using the third and fourth buttons from the left as -/+ buttons respectively, you can add or subtract time from the timer. Once you have selected the amount of time you would like to set the lock for, you can click the button to the far left to bring you back to the start menu. From here, you can press the second button from the left to start your timer lock. Once you start the timer, the servo rotates 90 degrees to effectively “lock” whatever it is installed into. When the timer expires, the servo rotates back 90 degrees the other way and “unlocks” the box. The Potentiometer on the far left can also be used to adjust the brightness of the LCD screen.

Preview of the Finished Build:

Shows Functioning Build

Code

Code for Arduino

        #include <Time.h> 
#include <TimeLib.h> 
 
#include <LiquidCrystal.h> 
 
#include <EEPROM.h> 
#include <Servo.h> 
 
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); 
 
Servo myServo; 
 
const int BackButtonPin = 6; 
const int StartButtonPin = 7; 
const int MinusButtonPin = 8; 
const int PlusButtonPin = 9; 
 
int settingHours = 0;    
int settingMinutes = 0;   
int settingSeconds = 0;   
time_t settingTime = 0; 
 
int activeHours = 0; 
int activeMinutes = 0; 
int activeSeconds = 0; 
time_t activeTime = 0;  
 
 
time_t startTime = 0; 
time_t elapsedTime = 0; 
 
int BackButtonState = LOW; 
long BackButtonLongPressTime = 0; 
int StartButtonState = LOW; 
int PlusButtonState = LOW; 
int MinusButtonState = LOW; 
int BackButtonPrevState = LOW; 
int StartButtonPrevState = LOW; 
int PlusButtonPrevState = LOW; 
int MinusButtonPrevState = LOW; 
bool BackButtonPress = false; 
bool BackButtonLongPress = false; 
bool StartButtonPress = false; 
bool PlusButtonPress = false; 
bool MinusButtonPress = false; 
 
bool locked = false; 
 
const int READY = 0; 
const int SETTINGS = 1; 
const int LOCKED = 2; 
const int UNLOCKED = 3; 
 
int activeState = READY;     
  
 
int timeData = 0;   
 
void setup() { 
 
  lcd.begin(16, 2); 
  pinMode(BackButtonPin, INPUT); 
  pinMode(StartButtonPin, INPUT); 
  pinMode(PlusButtonPin, INPUT); 
  pinMode(MinusButtonPin, INPUT); 
  myServo.attach(10); 
  Serial.begin(9600); 
  myServo.write(90); 
  
} 
 
void loop() { 
   
  StartButtonPress = false; 
  PlusButtonPress = false; 
  MinusButtonPress = false; 
 
  BackButtonPress = false; 
  BackButtonLongPress = false; 
  BackButtonState = digitalRead(BackButtonPin); 
  if(BackButtonState != BackButtonPrevState) 
  { 
    BackButtonPress = BackButtonState == HIGH; 
    BackButtonPrevState = BackButtonState;  
 
  } 
  else 
  { 
    if(BackButtonState == HIGH) 
    { 
      BackButtonLongPressTime++; 
      if(BackButtonLongPressTime == 100) 
      { 
        BackButtonPress = false; 
        BackButtonLongPress = true; 
        BackButtonLongPressTime = 0; 
      } 
    } 
    else 
    { 
      BackButtonLongPressTime = 0; 
      BackButtonPress = false; 
      BackButtonLongPress = false; 
    } 
  } 
 
  StartButtonPress = false; 
  StartButtonState = digitalRead(StartButtonPin); 
  if(StartButtonState != StartButtonPrevState) 
  { 
    StartButtonPress = StartButtonState == HIGH; 
    StartButtonPrevState = StartButtonState; 
  }  
 
 
  MinusButtonPress = false; 
  MinusButtonState = digitalRead(MinusButtonPin); 
  if(MinusButtonState != MinusButtonPrevState) 
  { 
    MinusButtonPress = MinusButtonState == HIGH; 
    MinusButtonPrevState = MinusButtonState; 
  } 
 
  PlusButtonPress = false; 
  PlusButtonState = digitalRead(PlusButtonPin); 
  if(PlusButtonState != PlusButtonPrevState) 
  { 
    PlusButtonPress = PlusButtonState == HIGH; 
    PlusButtonPrevState = PlusButtonState; 
  } 
 
  switch(activeState) 
  { 
    case READY: 
    myServo.write(90); 
      if(BackButtonPress) 
      { 
        Reset(); 
      } 
      if(BackButtonLongPress) 
      { 
        activeState = SETTINGS;  
 
      } 
      if(StartButtonPress) 
      { 
        activeState = activeState == READY ? LOCKED : READY; 
        if(activeState == LOCKED) 
        { 
          startTime = now(); 
        } 
      } 
      break; 
 
    case SETTINGS: 
    myServo.write(90); 
      if(BackButtonPress) 
      { 
        settingTime = settingSeconds + (60 * settingMinutes) + (3600 * settingHours); 
        activeHours = settingHours; 
        activeMinutes = settingMinutes; 
        activeSeconds = settingSeconds; 
        timeData = 0; 
        activeState = READY; 
      } 
      if(StartButtonPress) 
      { 
        timeData++; 
        if(timeData == 3) 
        { 
          timeData = 0; 
 
        } 
      } 
      if(MinusButtonPress) 
      { 
        switch(timeData) 
        { 
          case 0:  
            settingHours--; 
            if(settingHours == -1) 
            { 
              settingHours = 99; 
            } 
            break; 
          case 1:  
            settingMinutes--; 
            if(settingMinutes == -1) 
            { 
              settingMinutes = 59; 
            } 
            break; 
          case 2:  
            settingSeconds--; 
            if(settingSeconds == -1) 
            { 
              settingSeconds = 59; 
            } 
            break; 
        }  
 
      } 
      if(PlusButtonPress) 
      { 
        switch(timeData) 
        { 
          case 0:  
            settingHours++; 
            if(settingHours == 100) 
            { 
              settingHours = 0; 
            } 
            break; 
          case 1:  
            settingMinutes++; 
            if(settingMinutes == 60) 
            { 
              settingMinutes = 0; 
            } 
            break; 
          case 2:  
            settingSeconds++; 
            if(settingSeconds == 60) 
            { 
              settingSeconds = 0; 
            } 
            break; 
        } 
      } 
 
      break; 
     
    case LOCKED: 
    myServo.write(0); 
      if(StartButtonPress) 
      { 
        activeState = READY; 
      } 
      if(BackButtonPress) 
      { 
        Reset(); 
        activeState = READY; 
      } 
      break; 
 
    case UNLOCKED: 
    myServo.write(90); 
      if(BackButtonPress || StartButtonPress || MinusButtonPress || PlusButtonPress) 
      { 
        activeState = READY; 
      } 
      break; 
  } 
 
  switch(activeState) 
  { 
    case READY: 
    case SETTINGS:  
 
      break; 
    case LOCKED: 
      activeTime = settingTime - (now() - startTime); 
      if(activeTime <= 0) 
      { 
        activeState = UNLOCKED; 
      } 
      break; 
  } 
 
  lcd.setCursor(0, 0); 
  switch(activeState) 
  { 
    case READY: 
      lcd.print("Ready: Start    "); 
      lcd.setCursor(0, 1); 
      lcd.print(activeHours); 
      lcd.print("  "); 
      lcd.print(activeMinutes); 
      lcd.print("  "); 
      lcd.print(activeSeconds); 
      lcd.print("     "); 
      break; 
    case SETTINGS: 
      lcd.print("Set Timer:  "); 
      switch(timeData) 
      { 
        case 0: 
 
          lcd.print("HRS "); 
          break; 
        case 1: 
          lcd.print("MINS"); 
          break; 
        case 2: 
          lcd.print("SECS"); 
          break; 
      } 
      lcd.setCursor(0, 1); 
      lcd.print(settingHours); 
      lcd.print("  "); 
      lcd.print(settingMinutes); 
      lcd.print("  "); 
      lcd.print(settingSeconds); 
      lcd.print("     "); 
      break; 
    case LOCKED: 
      lcd.print("Waiting...       "); 
      lcd.setCursor(0, 1); 
      if(hour(activeTime) < 10) lcd.print("0"); 
      lcd.print(hour(activeTime)); 
      lcd.print(": "); 
      if(minute(activeTime) < 10) lcd.print("0"); 
      lcd.print(minute(activeTime)); 
      lcd.print(": "); 
      if(second(activeTime) < 10) lcd.print("0"); 
      lcd.print(second(activeTime)); 
 Logan Ritten  
 
      break; 
    case UNLOCKED: 
      lcd.print("   UNLOCKED!   "); 
      lcd.setCursor(0, 1); 
      lcd.print("              "); 
      break; 
  } 
  delay(10); 
} 
 
void Reset() 
{ 
  activeState = READY; 
  activeHours = settingHours; 
  activeMinutes = settingMinutes; 
  activeSeconds = settingSeconds; 
}

Credits

LoganSpace42

0 projects • 2 followers

Arduino Lock Box

Things used in this project

Hardware components

Story

NOTE:

So, Why Build This?

Preview of the Finished Build:

Schematics

Wiring Diagram

Flow Chart

Code

Code for Arduino

Credits

LoganSpace42

Comments

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Arduino Lock Box

Arduino Lock Box

Things used in this project

Hardware components

Story

NOTE:

So, Why Build This?

Preview of the Finished Build:

Schematics

Wiring Diagram

Flow Chart

Code

Code for Arduino

Credits

LoganSpace42

Comments

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