Make: Electronics by Charles Platt (classic books to read TXT) 📗

tools are not suitable for this kind of delicate work. A miniature handsaw (a.k.a. a “hobby saw”) is ideal for trimming things to fit. X-Acto makes a range of tiny saw blades. I suggest the #15 blade, plus the handle that it fits in, shown in Figure 3-14. Available online from Tower Hobbies, Hobbylinc, ArtCity, and many other arts/crafts sources. Also look for the larger X-Acto saw blade, #234 or #239, which you can use for cutting perforated board.

Figure 3-14. X-Acto makes a range of small saw blades that are ideal for cutting square holes to mount components in plastic panels.

Recommended: Miniature vise

A miniature vise can do things that the helping hand cannot. I use mine when I’m sawing small pieces of plastic and as a dead weight to anchor a piece of perforated board while I’m working on it. See Figure 3-15.

Figure 3-15. This one-inch vise is available from the McMaster-Carr catalog.

Look for a cast-iron vise that is listed as being 1 inch or slightly larger, available from Megahobby, eBay, and other arts/crafts sources. Also consider the PanaVise, which has a tilting head to allow you to turn your work to any angle.

Recommended: Deburring tool

A deburring tool instantly smoothes and bevels any rough edge (when you have sawn or drilled a piece of plastic, for instance) and also can enlarge holes slightly. This may be necessary because some components are manufactured to metric sizes, which don’t fit in the holes that you drill with American bits. Your small local hardware store may not stock deburring tools, but they are very inexpensively available from Sears, McMaster-Carr, KVM Tools, or Amazon. See Figure 3-16.

Figure 3-16. This cunning little blade, safety-tipped with a round bump on the end, removes rough edges from saw cuts with a single stroke, and can enlarge holes that are almost big enough—but not quite.

Optional: Hand-cranked countersink

You need a countersink to bevel the edges of screw holes to accept flat-headed screws. If you use a countersink bit in an electric drill, it won’t give you precise control when you’re working with thin, soft plastic.

Handheld countersinks that you grasp and turn like a screwdriver are easy to find, but McMaster-Carr (catalog item 28775A61) is the only source I’ve found for a hand-cranked tool that is much quicker to use. It comes with a set of bits, as shown in Figure 3-17.

Optional: Pick and hook set

Made by Stanley, part number 82-115, available from Amazon and hardware stores. You can find imported imitations for a few dollars less. See Figure 3-18.

Optional: Calipers

These may seem like a luxury, but are useful for measuring the external diameter of a round object (such as the screw thread on a switch or a potentiometer) or the internal diameter of a hole (into which you may want a switch or potentiometer to fit).

I like Mitutoyo calipers, and the low-end model 505-611 (shown in Figure 3-19) does everything I need. You can find cheaper brands, but economizing on precision measuring tools may not be a wise policy in the long term. The manufacturer’s site will show you all their available models, after which you can Google “Mitutoyo” to find retail sources.

Figure 3-17. You spin this countersink tool like a hand crank to add just the right amount of bevel to a hole, so that it will accommodate a flat-head screw.

Figure 3-18. This pick-and-hook set is useful in many unexpected ways.

Figure 3-19. Calipers can be digital (which automatically convert from millimeters to 1/64 inch to 1/1,000 inch), or analog like these (so you never need to worry about a dead battery).

Supplies

Solder

This is the stuff that you will melt to join components together on a permanent (we hope) basis. You need some very thin solder, size 0.022 inches, for very small components, and thicker solder, 0.05 inches, for heavier items. Avoid buying solder that is intended for plumbers, or for craft purposes such as creating jewelry. A range of solder thicknesses is shown in Figure 3-20. You want to make sure to get lead-free solder.

Figure 3-20. Spools of solder in various thicknesses.

Electronics solder has a nonacidic rosin core that is appropriate for electronic components. Rolls of solder are available from all hobby-electronics sources including All Electronics, RadioShack, and Jameco, or search for “electronic solder” on Amazon.

Wire

You’ll need some stranded wire to make flexible external connections with the circuit that you’ll be building. Look for 22-gauge stranded hookup wire, in red, black, and green, 10 feet (minimum) of each.

If you want to install the intrusion alarm after completing that project in Experiment 15, you’ll need white-insulated two-conductor wire of the type sold for doorbells or furnace controls. This is available by the foot from Lowe’s, Home Depot, Ace Hardware, and similar stores. You’ll decide how much to buy after you measure the distances between the magnetic sensor switches that you decide to install.

Heat-shrink tube

For use in conjunction with your heat gun, described previously. You’ll need a range of sizes in any colors of your choice. See Figure 3-21. Check RadioShack part 278-1627, other electronics suppliers, or your local hardware store. Prices will vary widely. You can buy the cheapest.

Copper alligator clips

These absorb heat when you are soldering delicate components. The Mueller BU-30C is a full-size solid copper alligator clip for maximum heat absorption. RadioShack sells smaller clips (part number 270-373, shown in Figure 3-22) that are suitable for tiny components.

Figure 3-21. Slide heat-shrink tubing over a bare joint and apply heat from a heat gun to make a tight insulating seal around the joint.

Figure 3-22. These small clips absorb heat to protect components when you’re soldering them.

Perforated board

When you’re ready to move your circuit from a breadboard to a more permanent location, you’ll want to solder it to a piece of perforated board, often known as “prototyping board” but also called “perfboard.”

You need the type that has copper strips etched onto the back, in exactly the same “breadboard layout”