Building a robot

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Building a Robot

Our type of competition robotic vehicle is low-cost, but high performance, allowing each team of one or two students to design and build their own unique vehicle within a few constraints: max. length 8 in., max. width 6.5 in., max. wheel diameter 3.5 in., max. voltage to servos 6 V., 2 powered wheels only. All else is fair game to the creator. We keep a box with a variety of sheet metals, plastics, and hardboard from which students may select, or bring their own. No two vehicles are ever made the same.

Each vehicle can be adapted to operate autonomously with a variety of sensors responding to the students's programming of the microcontroller, or it can be adapted to radio control for certain competitions. The initial cost of materials to make one of these vehicles is about $75, purchased from a variety of sources. In succeeding years, they are disassembled, redesigned and built again at trivial cost.

The following shows the construction of one example...

1 - A Parallax microcontroller costs about $30, the two full-rotation servos about $13 each. The breadboard from Allelectronics.com is $4, other electronics at trival cost from Jameco.com, toy wheels and other stuff from whereever.
2 - We use a variety of Parallax BS1 and BS2 microcontrollers, but other brands could be used also.

3 - Laptop computers are best 'cause you can stack 'em in a cabinet. the cheapest, oldest ones, which no one wants anymore, are best -- you can get 'em just about free, and they still have the parallel and serial ports convenient for cable connections. We got ours donated from the IRS.
4 - Cheap tools, you can't beat Harbor Freight (www.harborfreight.com). The hand tools shown are $2-$3 apiece. A 12" plastic tool box will hold tools and the finished robot. One electric drill will suffice for the classroom. We use a small drill press.
5 - Start by cutting a piece of sheet aluminum to make the servo mounts.

6 - Drill holes and bend the mounts... 7 - screw the hubs onto the wheels ... 8 - and, drilling holes to mount the servos onto the chassis platform.

9 - Bending a piece of aluminum for the battery mount, then ... 10 - screwing it onto the platform, then ... 11 - use velcro to attach everything else.

12 - Attaching some lever switches onto a strip of plastic to make a "touch-sensor" assembly, ... 13 - soldering some wire to the switches, ... 14- wiring up circuits on the breadboard, and ...

15 - You're ready to roll! The whole process takes about 6 hours of student time. 16 - Adriana working on the "Hornet".

17 - Esmeralda with her "Dragonfly"

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