Tech club builds floating spiders

DN Staff

April 8, 2002

5 Min Read
Tech club builds floating spiders

The lecturer, a cyberartist named Remo Campopiano, stands before a whiteboard and conducts a review of servomotors and their application to robotics. He asks questions about servos and the pulse trains that drive them. The attendees answer his questions readily; they obviously know their stuff.

The lecture attendees range from age 8 to 11, all members of the Robotics Art Club (, a two-year-old group here that combines art and technology. Already the group, under Campopiano's guidance, has built a fleet of dancing robotic waterspiders that have performed at the Boston Cyberarts festival and at Waterplace Park in Providence, RI. Now the group is planning to add features to the spiders and take on some new projects, such as a remotely operated blimp. They also have plans to build remote-control robots that will chase rats in a maze.

Genius kids? Science and math whizzes? Not at all. "They're just ordinary kids," says Campopiano. Most, he adds, come from parents who do "physical" things, such as auto mechanics.

Campopiano is no ordinary mentor, however. An accomplished artist, he has won a prestigious fellowship from the National Endowment for the Arts. He has recently exhibited at the Boston Cyberarts Festival and at the Boston-area DeCordova Museum. And one of his sculptures, "Cement Tree," is on display near the Trinity Repertory Theater in downtown Providence.

Like the kids he works with, Campopiano likes to build things. From his father, who was in construction, he and his brothers learned how to handle everything from hammers to backhoes. Recently, he's been learning electronics, and teaching the kids about it even as he learns it himself. Club membership varies between four and seven, plus some of the kids' parents.

One of their challenges was to mend some broken legs. Each water spider has a 6-foot PVC frame surrounding a hollow acrylic sphere. Paddles attached to the sphere provide locomotion when 12V motors rotate the sphere under control of a microcomputer. The original paddles kept breaking, though, until one of the kids came up with a clever idea: Instead of using simple slats as paddles, make the paddles in pairs by bending a strip of acrylic into a U shape. The extra strength of the revised paddles was just what was needed.

The kids have also learned about power efficiency in the project. The spiders' first design, in which motors rotated the sphere via a bicycle chain, didn't provide enough drive energy. Drive power increased dramatically, however, when Campopiano replaced the bicycle chain with a cogged, rubber drive belt molded directly to the inside of the sphere.

While the original model drove only forward and backward, the kids soon taught it to turn by splitting each spider's sphere into two hemispheres, with a separate motor driving each one. Now, by separately turning each motor on or off, they can make the spiders go straight or arc to the left or right. By running one motor forward and the other in reverse, they can make a spider spin in place, or even "dance."

The kids had to learn that form follows function, when they tried to add big, evil eyes and scary fangs to the creatures-Campopiano had a tough time convincing them to keep it simple.

Along the way, the club has had outside help from a variety of sources. For example, Michael Oliveira, Sr., a mechanic and welder and father of club members Michael, Jr., 11, and Evan, 8, built a special crane to lower the spiders into the water. Engineer Ashutosh Vighne, a Campopiano family friend, provided valuable assistance with electronic controls and programming. Club members' mothers made "scientist" lab coats that the kids wore during the waterspiders' public performances.

Corporate sponsors have also helped, donating money, materials, and services. Parallax, Inc. ( donated the Basic Stamp microcontrollers that provide control of the spiders. A local Volkswagen dealer donated money and painted the spiders in bright Volkswagen colors. And a local fabricator made the waterspiders' feet in return for a website design (Campopiano's main source of income).

They have ambitious goals for future projects. Waterspider power consumption, for example, needs to be reduced-or battery capacity increased-so that the spiders can operate for as long as three or four hours at a time in their public performances. Simply adding more 12V motorcycle batteries would make the spiders too heavy. A planned waterspider upgrade will also add proximity sensing to keep the spiders from running into each other.

And in the long term, Campopiano envisions a solar-panel raft where the spiders would go to recharge when they sense that their batteries are running low. He sees that situation existing after a city "adopts" the spiders as a semi permanent display in a public pond. He would even like to make the spiders appealing, friendly, and interactive. "You could call them over," he says, "and they'd come like ducks."

What kids can expect to get from the club activities is fun, with an emphasis on doing and learning. For example, Campopiano and 11-year-old Alex Croome together attended a two-day seminar to learn how to program the Parallax Basic Stamp that controls the waterspiders. "I was the only kid there," Alex says. "Everyone else was like from really important factories and stuff." But the seminar instructors "sort of adopted" Alex, Campopiano says, and he came away with a basic knowledge of programming.

Learning also comes from family involvement. For example, the Oliveira kids' dad has always involved Michael and Evan in his work as a mechanic, and now he's learning electronics along with them in their club activities. His mentoring nature is evident at a meeting when Campopiano asks for ideas on how a servomotor might be applied. After a long pause, Oliveira provides a hint by mentioning a throttle.

"Oh, yeah!" yells 11-year-old Michael in reply. You can see from the light in his eyes that he knows all about throttles. You can also tell that he sees-very clearly-how he might someday use a servo to control one.

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