The first unit is fully assembled, programmed and tested!

The operation is fairly simple:

• pressing a button increments the corresponding counter,
• it also makes the LED on that button shine for 400 milliseconds,
• while the LED is shining, pressing any buttons has no effect,
• it also makes the display work for 30 seconds,
• the display shows the state of a counter,
• it switches between the three counters every 2 seconds,
• the counter being displayed is indicated by letters "a", "b" and "c",
• to reset the counters switch the device off and on again.

I'm quite happy with how it came out. The only problem is that the LEDs on the buttons are fairly weak and not well visible in a bright room. They will be probably fine in a conference room, though.

Finally, a movie: