Most buzzers give off sound in the 2–4 kHz range. Buzzers aren’t very dis-
criminating when it comes to voltage: Their ratings are approximate, meaning
that a 12V buzzer is absolutely happy to work with a 9V power supply.Buzzers have two leads, and you have to connect a buzzers the right way
round. The red lead is always positive (+).The Nuts and Bolts of Building Materials ...................................................
A pure electronics project might just consist of a breadboard containing com-
ponents and wires. In most cases, though, you’ll also want to create some
sort of container or chassis to hold the project. For example, if you build a
simple radio, you might put the guts of it in a box and drill holes to place the
dials and speaker.You can buy ready-made boxes or other containers and make them work for
your project. You can also build your own out of various materials.Plastic.....................................................................................................
ABS (please don’t ask what this acronym means; we could tell you, but you
couldn’t pronounce it) plastic boxes are available from most electronics sup-
pliers. These are lightweight, sturdy, waterproof, and handy for housing your
gadgets. We use a plastic box in Chapter 11 to house a remote control.The plus with plastic boxes is that components such as switches are
designed to be mounted on boxes or panels with thin walls. Therefore,
mounting these components on these plastic boxes is often easier than on
wooden boxes.The downside is that cutting clean openings in plastic is harder than in wood —
for example, to insert speakers.Wood ......................................................................................................
We like to use wooden boxes to house many of our projects because, well,
they look nice. We found simple, unfinished wooden boxes at a national craft
supply superstore (Michaels), but any craft store probably stocks them.52 Part I: Project Prep