Kinetic Contraptions: Build a Hovercraft, Airboat, and More with a Hobby Motor
6 Getting Started TOOLS Tools from the following list may be required to build the kinetic contraptions in this book Then again you can always improvise As my dear old dad said You have to have the right tools for the job But if you don’t you still have to do the job (cid:128) Drill with bits (cid:128) File (cid:128) Hacksaw (cid:128) Hammer (cid:128) Hot glue guns with plenty of glue sticks low temperature works fine and is safer but high temperature bonds a bit better (cid:128) Knives box cutter hobby knife and razor blade (cid:128) Needle-nose pliers (cid:128) Pliers (cid:128) Ruler (cid:128) Scissors (cid:128) Screwdrivers flat and Phillips large and small (cid:128) Side Cutter (cid:128) Vice or C-clamps (cid:128) Wood saw MATERIALS AND SUPPLIES It is good to have the following stuff on hand to do these projects and as inspiration for thousands of other projects You can check my Web site www curtgabrielson com for more information on where to find materials (cid:128) Motors Buy one or two at an electronics shop or order a dozen on the Web Or you can rip them out of old toys (cid:128) Batteries Cheap batteries at 99-cent stores don’t last long but they’re what we use most of the time If you screw up and leave a project connected it will drain a high-quality high-cost battery just as completely as a cheap one The best option however is to invest in rechargeable nickel-metal hydride NiMH batteries and a charger They’ll last for years if you take care of them so they
Getting Started 7 are cheaper than any other type in the long run Even solar-powered chargers are available (cid:128) Electrical Wire Thin copper wire from phone or Internet connections is used on most of these projects You could also use bare copper wire but if it contacts another wire you’ll have a short circuit For the projects in the Exploring Motors section page 149 you’ll want magnet wire of 24 to 30 gauge If you buy just one size get 26 gauge You can buy it on the Web or at a motor repair shop or you can rip apart an old transformer or large motor For the speed control you can find an old toaster at a resale shop and rip the heating element wire out of it (cid:128) Structural Wire Baling wire is useful as are clothes hangers picture-hanging wire wire twisty ties pipe cleaners and even old bicycle spokes (cid:128) Kitchen and Household Stuff Disposable utensils cups and plates all different types bamboo skewers toothpicks clothespins straws paper and aluminum foil (cid:128) Office Supplies Binder clips pencils paper clips large and small stapler rubber bands of all sizes tacks push pins and brass fasteners (cid:128) Corks Film Canisters a dying breed thanks to digital cameras and Thread Spools In really old project books you’ll see a lot of references to thread spools In many cases you used to be able to substitute a film canister but these days it is almost as easy to find a thread spool as a film canister A few other things can fill in for these two endangered species salsa cups medicine bottles and corks (cid:128) Wheels Bottle lids film canister lids checkers poker chips large beads and wood circles cut with a hole saw (cid:128) Tape Black electrical is the most commonly used tape in these projects but transparent masking and duct are also useful to have around (cid:128) Fasteners Nails of various sizes can be used or for an even stronger hold you can use drywall screws and a hand drill (cid:128) Wood Three standard sizes for light construction paint paddles for stirring a gallon of paint usually free at the paint shop so grab a handful tongue depressors and craft Popsicle sticks For beefier projects 1-by-2-inch furring strips are quite useful and a small pile of scrap wood from ¼ inch to ¾ inch thick is needed for baseboards and other parts Wood dowels ¼ inch to 5 16 inch are quite useful (cid:128) Decorations Paint markers glitter ribbons colored paper stickers puff balls pipe cleaners etc
9 Safety I could list a lot of specific safety procedures but most of the time it comes down to this be cautious and don’t be stupid Safety should always be your first priority If you don’t put it first you’ll get a bloody finger or a damaged cornea instead of a fun project Most of the injuries kids have suffered at the Watsonville Science Workshop have come from hot glue and knives Here are a few pointers for avoiding injuries (cid:128) Wear safety glasses when using any power tool (cid:128) Never touch the tip of the hot glue gun and don’t touch the glue when it comes out If you do get hot glue on you wipe it off as quickly as you can or it will continue burning If you do happen to get burned you can learn a lot about the amazing function of skin as you watch it heal (cid:128) Always cut away from yourself with a knife (cid:128) Keep your other hand away from the tool when using a knife hammer saw or drill (cid:128) Unplug something before you take it apart Even then capacitors may be holding a charge that could hurt you Don’t open or disassemble anything that says Danger or High Voltage on it definitely not a TV or computer monitor (cid:128) Get adult help if you have the least concern about the safety of a procedure That’s what they’re there for
11 Basic Circuitry Two main components batteries and motors will make your kinetic contraptions go To be specific batteries provide the energy for your machine and the motor provides the force Electrical energy is stored in a battery Generally speaking the bigger a battery is the more energy it stores However there is not a direct connection between the size of a battery and the voltage it gives For example AAA AA C and D batteries all give about 1 5 volts But you can bet your best wire strippers that the D battery will last a lot longer than the AAA in a given circuit If your contraption must be lightweight go for the smaller batteries but understand there’s a tradeoff Rectangular 9-volt batteries are actually six cells of 1 5 volts each rip a dead one apart and see for yourself Alkaline batteries contain nastier chemicals then 9-volt batteries so don’t rip alkalines apart I’ve had bad luck using 9-volt batteries for motors Such small cells just don’t hold enough energy for a motor or other high-current application Once connected the battery meets a hasty death Chemicals within a battery stand ready to carry out two separate reactions one producing excess electrons the other consuming them If you connect those two reactions with a conducting path the reactions will begin and the electrons will flow from one to the other making electricity direct current A copper wire works well for making the path if you use just copper wire an enormous gush of current will flow from one end of the battery to the other and your battery will die within a few minutes It may also get hot from the chemical reactions happening so fast The wire will get hot too from all the collisions among
