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"  Mars is hot! Well, actually, it&amp;#039;s frigid. But since searching for signs of former life on the Red Planet is all the rage, we asked Jenny Young of the Brooklyn Robot Foundry to help us devise a minirover project. It teaches the basics of electrical circuitry, motors, and even lighting. The build is complex enough to engage experienced gearheads, yet simple enough for novices to do with a little help. They&amp;#039;ll learn the fundamentals of robotics\u2014for a fraction of NASA&amp;#039;s budget. Degree of Difficulty: 6/10 Ages: 7+ Build Time: 2 hours Parts Cost: $25 Materials and Tools \u2022 Elenco 2-in-1 Gearbox kit \u2022 AA-battery case with switch \u2022 3-volt 10-mm LED (one that can handle 3 volts or more) \u2022 Two AA batteries \u2022 22-gauge multistrand black wire, cut into two 6-inch lengths \u2022 22-gauge multistrand red wire, cut into two 6-inch lengths \u2022 One baby-bottle cap or other plastic-dome piece (large bottle top, capsule for vending-machine toys) \u2022 Two 2-inch-diameter handballs or other hollow, squishy balls \u2022 \u00BD-inch-thick foam board, cut into a 2.5 x 4.5\u2013inch piece \u2022 One wine-bottle cork \u2022 Aluminum foil, crepe paper, construction paper, gift paper (optional) \u2022 Pipe cleaners (optional) \u2022 Hot-glue gun and glue sticks \u2022 Drill and 7&amp;amp;amp;fracsl;64-inch drill bit \u2022 Wire cutter/stripper \u2022 Ruler, scissors \u2022 Electrical tape, adhesive tape  Build the Engine 1. Assemble the Elenco 2-in-1 Gearbox by following the instructions included in the kit. For this project, use the longest of the three shafts provided as the front axle and disregard the nylon connectors. The rover&amp;#039;s speed is determined by the cogs you choose: Gear ratios of 1:60 and 1:288 are fast and slow, respectively. 2.Strip 3/4 inch of insulation from each end of two 6-inch black wires and two 6-inch red wires. 3.Thread the end of a black wire through the hole in one of the motor terminals and secure it by folding the wire back on itself and twisting; repeat the process with red wire at the other terminal. 4.Carefully separate the legs of the LED; they&amp;#039;re fragile, so take care not to break them off. 5.Tightly wrap one end of the exposed part of the black wire around the short leg of the LED; do the same with the red wire around the long LED leg. 6.Strip \u00BD inch of the battery-case wire ends. 7.Twist together the black wires from the motor, battery case, and LED; repeat with red wires.  8.Wrap all exposed wires tightly with electrical tape, including those around the legs of the LEDs and the terminals on the motor.  9.Put batteries in case; flip switch to test circuit.  Assemble the Craft 1. Drill a 7/64-inch hole into each ball. Slide the balls onto the axle ends. 2.Decorate the piece of foam by wrapping it in foil, construction paper, or gift paper\u2014go nuts!  3.Use a glue gun to secure the gearbox to the body. 4.On the opposite end, glue on the cork. You may need to cut down the cork to ensure that the body is level. Let the glue dry. 5.Flip over the body and glue the battery pack near one end of the surface; let dry. This is the top of the rover&amp;#039;s body.  6.Glue the LED terminals and wires to the top of the rover.  7.Glue the translucent baby-bottle cap to the top of the rover, covering the LED. Let dry. 8.Decorate with pipe cleaners, crepe paper, or other gewgaws to make your rover look galactically awesome! "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/technology/a8824/build-this-25-toy-mars-rover/>