A green roller coaster twists and turns in the air above the entrance to the Children's Museum of Pittsburgh. But this attraction isn't for human riders — the coaster's cars are instead filled with plants and a solar panel that triggers the ride to stop and start.

The coaster is one of 11 BigBot robotic art installations around the city, part of a citywide celebration of robotics that aims to take technology out of university classrooms and make it accessible to everyone. Dubbed to coincide with the city's 250th anniversary celebration, Robot 250 begins Friday as a mix of robotics and artistry.

"It bends the idea of what robotics is about and who it's for," said Illah Nourbakhsh, an associate professor of robotics at Carnegie Mellon University's Robotics Institute and one of the originators of the Robot 250 idea.

Robotics isn't just about industrial automation and isn't only for engineers, he said. Instead, Nourbakhsh said, robotics can be a way for people of any age to express themselves or to affect their communities.

"It's really a way to give a technological tool to people to have a stronger voice," he said.

The planning for Robot 250 started more than a year ago — while Nourbakhsh and others ate a lunch of crepes at a restaurant in the city's Oakland section. They knew Pittsburgh would be an ideal place to start such a program because of the city's unique mix of a vibrant arts community as well as world-renowned robotics and arts programs.

Over the next year and a half, he and his collaborators found funding for the massive project, brought their programming to community groups such as YMCAs and gave workshops to dozens of teachers so that kids and adults could create their own robots. Other participants were given Gigapan robotic cameras that capture large panoramic views with exacting detail.

The results were robots big and small, complex and simple: One woman used a Polaroid camera and other parts to create a robot that took pictures of cars speeding on the street in front of her home, while a group of people made a conceptual robot that would automatically salt the city's bridges in the winter and hopefully encourage more people to walk the bridges even in cold weather.

"We wanted to build a robot that would show how we could help the community," said Kyle Buzard, 11, a seventh grader at Allegheny Traditional Academy.

He and several other classmates created robotic flower petals decorated with images they created to represent good — healthy things like fruits and vegetables — and bad — such as alcohol abuse or drugs. Buzard said the robots could be placed around a community to show people the affects of good and bad choices.

The Gigapan photos along with the community-created robots will be on display at locations all over the city starting Friday, part of the two-week official Robot 250 celebration. The 11 BigBots, which include the plant roller coaster, also are placed at various museums and galleries, including a 12-foot tall "You're .1" foam hand that will sit atop The Andy Warhol Museum and a robotic sheep "lawn mower" that will be on the grass outside of the Phipps Conservatory and Botanical Gardens.

One of the BigBots can be found in a courtyard outside of the art gallery known as The Mattress Factory, where 25 small robots sit randomly among tall grass and rocks. Like oversized crickets, the robots are connected through thin wires and have wooden beaks that make noise. Visitors to the courtyard can also control the robots.

Another BigBot is a roving one that is stopping at parks and other city attractions. Called the Look-See Tree, the robot is a tree made of steel, nylon, resin, tape and other materials that is pulled by a bicyclist. In holes in the tree, kids and adults can trigger robotic rabbits, birds and other critters to move.

Its creator, Carnegie Mellon student Ally Reeves, said the robot is meant to make people smile — but also has an environmental message because of the bicycle and a hand crank that charges a battery inside the tree.

The celebration also includes family activities, including listening to a robotic orchestra or making custom petals for robotic flowers at the Children's Museum. The Citiparks Roving Art Cart, which stops at city parks and playgrounds, will also encourage kids to make their own robots.

The entire Robot 250 event was sponsored by Carnegie Mellon University and the University of Pittsburgh and funded with nearly $2 million from the Heinz Endowments and the Grable and Benedum foundations.

Carl DiSalvo, a Carnegie Mellon graduate and now assistant professor at Georgia Tech University, was also one of the originators of the Robot 250 concept. Even after the two-week celebration ends, DiSalvo, Nourbakhsh and others will be working with a nearly $2 million grant to try to replicate the program in other cities. Their first stop is Atlanta.