Switching Basics and More 93Experiment 11: A Modular Project- If the alarm is triggered, what then? If someone forces open a window,
should the alarm stop sounding as soon as the window is closed again?
No, the alarm should lock itself on, until you turn it off. - How do you turn it off? Some kind of secret-code keypad would be good.
- But to avoid driving everyone crazy if the alarm is triggered when you’re
not there, it should eventually stop itself, perhaps after about 10 minutes.
At that point it should remain quiet but should light an LED to tell you
what happened. You can then press a reset button to switch off the LED.
Implementing the Wish List
I’ve compiled a wish list that seems likely to make the project at least five times
as complicated as it is already. Well, that’s what tends to happen when you go
beyond little demo circuits and try to design something that will be useful in
everyday life. Suddenly you find yourself having to accommodate all kinds of
circumstances and situations.
Actually, I can and will show you how to take care of all the enhancements on
the wish list, but I’m thinking that they will require us to get a little more seri-
ous about electronics projects in general first. If you’re going to build some-
thing ambitious, you’ll want to make it more permanent, and probably more
compact, than a breadboard with components pushed into it.
You will need to know how to connect everything permanently with solder, on
a piece of perforated board that you can install in a neat little project box with
switches and lights on the outside.
I’m going to deal with soldering and packaging in the next chapter. After that,
we’ll get back to the alarm project.