Edwin L. Aguirre
Each weekend, an estimated 54 million Americans mow their lawns, consuming about 800 million gallons of gasoline every year and producing tons of air pollutants.
According to the U.S. Environmental Protection Agency (EPA), lawn mowers (like snow blowers, chain saws, leaf blowers and similar gas-powered garden equipment) emit high levels of carbon monoxide, a colorless, odorless, poisonous gas.
“They also emit hydrocarbons and nitrogen oxides, pollutants that contribute to the formation of ozone,” states an EPA report. “While ozone occurs naturally in the upper atmosphere and shields the earth from harmful radiation, ozone at ground level is a noxious pollutant. Ground-level ozone impairs lung function, inhibits plant growth and is a key ingredient of smog.”
Samuel Hamill, a senior electrical engineering student from Lawrence, has created a prototype solar-powered push mower to help cut down on air pollution, gas consumption and noise.
“It’s a sustainable, environmentally friendly way of maintaining one’s lawn,” says Hamill, who is scheduled to graduate in May.
His design is part of his capstone project, with Prof. Samson Mil’shtein as faculty adviser. Alan Rux of the Assistive Technology Program supervises all the senior capstone projects.
Hamill’s solar panel generates up to 160 watts, enough to power two small DC motors — one for driving the blades of a regular reel mower to cut grass and the other for turning the solar panel. A pair of photoresistors helps the panel keep track of the sun as the mower moves back and forth across the lawn.
“You don’t need a storage battery to operate the mower,” explains Hamill. “It will run directly off the solar panel. But you can certainly add a battery if you want to mow on a cloudy day. On a sunny day, the panel can run the mower and recharge the battery at the same time.”