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 component in App Inventor is similar to an oven clock. It can
- Tell you information about the current time (and the date)
- Count down and do something useful after a set time has passed
One important difference between an App Inventor clock and a microwave oven clock is that an App Inventor Clock timer automatically restarts over and over again until you turn it off. Try that with a microwave, and you’ll quickly have burned food and a house on fire!
