Hi everybody,
I want to make a simple HH:MM:SS countdown timer with the UNO, presenting the countdown on a 1602 LCD Display.
I know how to wire everything up, but I just can't program a countdown, no matter what I do.
I was hoping you can help me making the program, or give me a written one.
Thank you so much and all the best.
I've never done it, but a quick search in google produce some pages that might help you.
Take a look and then let us know how you are doing it and any doubts that you might still have:
Arduino Countdown Timer:
http://www.hobbytronics.co.uk/arduino-countdown-timer
Another tutorial from where you can take some ideas for your code:
And the code for a Arduino Clock (maybe you can figure out a way to reverse the timer...):
http://zseries.in/project%20lab/tutorials/codes/lcd%20clock.txt
Good luck!
First step. Display HH:MM:SS on the LCD. Have you done that ?
How do you propose to hold the time ?
If held as discrete numbers for HH, MM and SS then decrement SS every second. When it gets to -1 reset it to 59 and decrement MM. Do the same for MM and HH.
If held as a number of seconds until zero then decrement it every second then call a routine that converts it to HH:MM:SS and displays it.