Читать книгу Electronics All-in-One For Dummies - Lowe Doug, Doug Lowe - Страница 89

Most project boxes are made of plastic or metal and have a detachable lid that’s held on with four screws, one at each corner of the lid. To gain access to the insides of the box, you simply remove the screws to release the lid.

The inside of the box may be completely smooth, or it may contain ridges or mounting studs designed to make it easier to mount components inside the box. If there are no such accoutrements inside the box, you’ll have to devise your own method of attaching the various bits and pieces that need to go inside. Here are some tips:

 You’ll need a good assortment of small drill bits to drill holes through the box to mount your components. You’ll need to drill holes to mount the circuit board as well as such things as battery holders, switches, LEDs, speakers, and whatever else your project may require.

 Make a good sketch of your project box and how its parts will be arranged before you start drilling holes. When you’re sure that you have everything laid out the way you want, use a marker to indicate the exact position of the holes you need to drill.

 To mount the circuit board, use standoffs to provide some empty space between the board and the case. A standoff is a screw that allows you to mount the board so that it is raised above the bottom of the project box. You can purchase standoffs from any electronic parts supplier, but they are surprisingly expensive, often as much as 45 cents each. If you have an ample supply of nuts and bolts, you can fashion your own standoffs simply by cutting a short length of plastic tubing — my favorite material is ¼-inch drip irrigation hose — and feeding a long bolt through it.

 Consider mounting the circuit board on the back of the lid rather than inside the body of the box. This sometimes frees up more room within the box for larger items such as batteries or a speaker.

 Most switches can be mounted to a box by drilling a hole large enough to allow the neck of the switch to pass through. The switch comes with a nut that you can tighten over the neck of the screw to secure the screw to the box.

 Some components don’t have mounting nuts to secure them to the box. For them, a small amount of epoxy or other glue can help set the component in place.

 Use stranded wire for connections within the project box. Stranded wire holds up better to the handling it occasionally gets when you open the box, for example, to change the batteries.