Chapter 7. Clocks and timers

Take a look at the clock on a microwave oven. If you had to tell an alien what it was for, what would you say? Does it just provide information about the time?

Normally, this kind of clock does two useful things:

1.  It tells you what time of day it is in hours and minutes.

2.  When the oven is cooking, it shows a countdown of how long is left and does something useful when the timer gets to zero: stops the oven and goes “Ping!”

It might also do other cool (or hot) stuff, like starting the oven at a preset time or changing cooking programs halfway through. Why all this talk about microwaves? Well, the Clock ...

Get Hello App Inventor! now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.