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In this project, we will use the Arduino Uno to control an LCD screen to show the current time and time that an alarm is set for. We will use buttons to set each time.
// Initialize variables to be used
int hour = 0; // Hour for current time int minute = 0; //
Minute for current time int second = 0; // Second for current time
int hour_a = 0; int // Hour for alarm time
minute_a = 0; // Minute for alarm time
bool am_pm = false; // AM/PM toggle flag. False is AM, True is PM
bool am_pm_a = false; // AM/PM toggle flag for alarm. False is AM, True is PM
int set_hr = 13; // Use pin 13 to set hour
int set_min = 12; // Use pin 12 to set minute int
set_am_pm = 11; // Use pin 11 to set am/pm
int set_hr_a = 10; // Use pin 10 to set hour for alarm int set_min_a = 9; // Use pin 9 to set minute for alarm int set_am_pm_a = 8; // Use pin 8 to set am/pm for alarm
int speaker = 7; // Pin to use for speaker
int quiet = 6; // Pin to stop the speaker
bool alarm = false; // Flag to toggle to keep alarming
bool quieted = false; // Flag showing quiet hasn't been pressed
int cur_time = 0; // Variable for current time
int etime = 0; // Variable for elapsed time
void setup() {
// Set up LCD screen
Serial.begin(9600); // Initialize Serial at 9600 baud
Serial.write(17); // Turn on the back light
Serial.write(24); // Turn the display on, with cursor and no blink
Serial.write(12); // Clear the screen
Serial.write(128); // Move cursor to top left corner
// Set pinModes pinMode(set_hr,
INPUT); pinMode(set_min, INPUT);
pinMode(set_am_pm, INPUT);
pinMode(set_hr_a, INPUT);
pinMode(set_min_a, INPUT);
pinMode(set_am_pm_a, INPUT);
pinMode(speaker, OUTPUT);
pinMode(quiet, INPUT);
// On initial power, have user set current time. Serial.print("Set the current time"); delay(2000);
Serial.write(12);
printTimes();
cur_time = millis(); // Store the current time
}
void loop() {
// Keep Time
keepTime();
// Check to see if it's time to alarm!
if((hour == hour_a && minute == minute_a && !quieted) || alarm){
tone(speaker, 2000, 500); // Output a 2000 Hz sound to the speaker for 500 ms
delay(500); // Delay 500 ms
if(!alarm){ // If alarm is off, turn it on
}
}
// If the user silences the alarm by pressing the quiet button, stop alarmingif(alarm && !quieted && digitalRead(quiet)){
alarm = false;
quieted = true;
}
// Reset the alarm
if(!alarm && quieted && minute != minute_a){ quieted = false;
}
// Check to see if the set pins go high, and if so, increment the corresponding valueif(digitalRead(set_hr) && hour < 12){
hour++;
printTimes();
debounce();
}
else if (digitalRead(set_hr) && hour == 12){ hour = 1;
printTimes();
debounce();
}
else{}
if(digitalRead(set_min) && minute < 59){
minute++;
printTimes();
debounce();
}
else if (digitalRead(set_min) && minute == 59){ minute = 0;
printTimes();
debounce();
}
else{}
if(digitalRead(set_am_pm) && am_pm){
am_pm = false;
printTimes();
debounce();
}
else if (digitalRead(set_am_pm) && !am_pm){ am_pm = true;
printTimes();
debounce();
}
else{}
if(digitalRead(set_hr_a) && hour_a < 12){
hour_a++;
printTimes();
debounce();
}
else if (digitalRead(set_hr_a) && hour_a == 12){
hour_a = 1;
printTimes();
debounce();
}
else{}
if(digitalRead(set_min_a) && minute_a < 59){
minute_a++;
printTimes();
debounce();
}
else if (digitalRead(set_min) && minute_a == 59){
minute_a = 0;
printTimes();
debounce();
}
else{}
if(digitalRead(set_am_pm_a) && am_pm_a){
am_pm_a = false;
printTimes();
debounce();
}
else if (digitalRead(set_am_pm_a) && !am_pm_a){
am_pm_a = true;
printTimes();
debounce();
}
else{}
}
it may think the button was presses several times when you only intended for it to be read once. Debounce() will freeze the program until the button is released. printTimes() updates the LCD screen, but since that was several commands, I typed them once and then can call the subroutine any time a time value changes.
// While any of the buttons are being pressed, stay in this function then delay 250 ms.
void debounce(){
while(digitalRead(set_hr) || digitalRead(set_min) ||
digitalRead(set_am_pm) || digitalRead(set_hr_a) ||
digitalRead(set_min_a) || digitalRead(set_am_pm_a)){} delay(250);
}
// Prints the updated times if there are any changes
void printTimes(){
Serial.write(12);
Serial.print("Current Time:");
Serial.write(148);
if(hour < 10){
Serial.print("0");
}
Serial.print(hour);
Serial.print(":");
if(minute < 10){
Serial.print("0");
}
Serial.print(minute);
Serial.print(":");
if(second < 10){
Serial.print("0");
}
Serial.print(second);
if (am_pm){
Serial.print("PM");
}
else{
Serial.print("AM");
}
Serial.write(168);
Serial.print("Alarm Set for:");
Serial.write(188);
if(hour_a < 10){
Serial.print("0");
}
Serial.print(hour_a);
Serial.print(":");
if(minute_a < 10){
Serial.print("0");
}
Serial.print(minute_a);
if (am_pm_a){
Serial.print("PM");
}
else{
Serial.print("AM");
}
}
// Increment the time parameters void
keepTime(){
etime = millis() - cur_time;
if(etime >= 1000 && second < 59){
second++;
cur_time = millis();
printTimes();
}
else if(etime >= 1000 && second == 59 && minute < 59){ second = 0;
minute++;
cur_time = millis();
printTimes();
}
else if(etime >= 1000 && second == 59 && minute == 59 && hour < 12){
second = 0; minute =
0; hour++; cur_time =
millis(); printTimes();
}
else if(etime >= 1000 && second == 59 && minute == 59 && hour == 12){
second = 0; minute =
0; hour = 1; am_pm =
!am_pm;
cur_time = millis();
printTimes();
}
else{}
}
6. That’s it!
Compile and upload and you’re all done!
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