I have an Arduino based countdown timer that counts down the number of minutes remaining to an event and displays them on an LCD. Since the event's start time is fixed, I have to re-calculate my countdown duration and update a constant in the sketch every time I upload it.
Is it possible to calculate the duration on the PC and set the starting value for the timer automatically? Perhaps using some kind of pre-compile script? Or perhaps through some kind of debugging features?
I'm not interested in adding RTC or other hardware to this project b/c (1) I don't have it handy and (2) there's very limited physical space in the already assembled project.
I'm currently using the Arduino IDE but I would be open to solutions that use other IDEs, or external components.