/* * In the last lesson, you turned a timer into a clock. Next you'll * add in an alarm function to that clock. The 'alarm' will be a * message displayed on the screen. * * To add this functionality, you'll create a set of * variables which will hold the time that the alarm should go * off and a check to trigger the alarm when reaching that time. */ #include "MakerScreenXVI.h" MakerScreenXVI lcd; int seconds = 50; int minutes = 59; int hours = 1; bool AMPM = 1; long timer; // Set the alarm times, currently set for 2:30 PM. // Because there isn't a 'second' variable, the alarm will last 1 minute. int alarmMinute = 0; int alarmHour = 2; bool alarmAMPM = 1; // This variable tells you if you should be showing the alarm message. bool alarmState = 0; //alarmState will equal either 0 or 1. void setup() { lcd.begin(); lcd.backlightOn(); timer = millis();//start the timer as equal to the internal counter. } void loop() { if (millis() - timer >= 1000){ seconds = seconds + 1; timer = timer + 1000; } // Insert the check into the seconds update so that it will // register the alarm once when the minute changes if (seconds >= 60){ seconds = seconds - 60; minutes = minutes + 1; // Reset alarmState every minute so the alarm goes off after // 60 seconds alarmState = 0; } if (minutes >= 60){ minutes = minutes - 60; hours = hours + 1; if (hours == 12){ AMPM = 1 - AMPM; } if (hours == 13){ hours = 1; } } /* * Combine 'if' conditions with && (shift + 7). * && (Boolean 'and') checks all of the conditions and performs * the code in the following {} block only if all are true. * This checks if the hours, minutes, and AMPM all match that of * the alarm */ if ((hours == alarmHour)&&(minutes == alarmMinute)&&(AMPM == alarmAMPM)){ // If all the current times match the alarm time, set // the alarm variable to 1 so that you're in 'alarm state'. alarmState = 1; } /* * Now that alarmState has been set, decide what to do. * If alarmState is 0, then you are in the normal non-alarm * mode, and display the time normally. * * Note that there are 4 'if' statements inside the alarmState 'if' * statement. These are only checked if alarmState is 0. This situation * shows how indentation, spacing, and placement of braces can increase * code clarity for yourself or anyone else who reads your code. */ if (alarmState == 0){ lcd.clear(); lcd.print(hours); lcd.print(":"); if (minutes < 10){ lcd.print("0"); } lcd.print(minutes); lcd.print(":"); if (seconds < 10){ lcd.print("0"); } lcd.print(seconds); if (AMPM == 0){ lcd.print(" AM");} if (AMPM == 1){ lcd.print(" PM"); } } // If alarmState is not 0, then display the alarm message: else{ lcd.clear(); lcd.print("Wake Up!"); } /* * You will see "Wake Up!" for one minute straight. * The void loop() is still running in the background, checking the * time against the alarm many times per second. When it finally sees * that alarmMinute no longer matches minute, it will display time again. * What is displayed is not all that is happening in a clock! */ delay(300); } /* * In this lesson, you modified your time checks to add in * the alarm function. Just like the AM/PM check, * you added this new check to be made when one of the time counters * ticks up (in this case, the minutes counter), so that it only * runs once each time that condition is met (every minute). * * You saw the use of two new additions to the * conditional checks: && and else. && combines multiple checks into one * statement. * * Else specifies what should happen when an 'if' statement is false, * covering all cases not addressed by the original 'if'. * * Try changing the 1000 in "if(millis()-timer>=1000)...." to a smaller * number. That will increase the 'speed of time' and allow you to more * quickly test your alarms. * * Think about how you could create an alarm each hour on the same minute. * Hint: You'll only need the 'delete' key! * * In the next lesson, you'll learn to set the time on the clock with a * button so that you don't have to carefully time your code uploads. * */ // (c) 2017 Let's Start Coding. License: www.letsstartcoding.com/bsdlicense