All the details of the design and how it works are available in my little electronic project's GitHub Repo (it is basically my open lab notebook, with a catalog of many projects now).
Here's a demo of it running a 5-minute countdown (I would be surprised if anyone watches the whole thing without skipping to the end!)..
There's a few things I set out to achieve:
- the 3x7 displays minutes in two digits, and tenths of minutes on the 3rd digit
- the Pomodoro countdown runs from at most 95 minutes, but default to start at 55 minutes (my preferred time block)
- the microprocessor measures reasonably accurate time for the countdown, but I'm not going to be upset if it is a little off (less than a minute)
- before starting the count, two buttons can be used to increase or decrease the countdown respectively, in increments of 5 minutes
- when the countdown has completed, the unit will flash for a period of time
- a button press resets the app for another countdown
- if no input, go to sleep
- if sleeping, a button press wakes up and resets the application
hi @donvukovic: I used a mix of 0.9mm copper wire for the main frame, 0.55mm copper wire for some of the internal connections, and the rest are just the leads of leaded components.