On a cold day in January, John Zimmer stands next to the waterwheel he built in his basement last winter. (Photos by Lisa Aciukewicz)

When he retired from his position as an engineer at Raytheon, John Zimmer never lost an engineer’s need to create something useful as well as handsome. After spending most of the winter of 2006 in his basement, Zimmer emerged last spring with the makings of the eight-foot-tall waterwheel that now spins in a seasonal stream just off Slough Road. The waterwheel, when not covered in ice, produces up to 100 watts of power, enough to power the amateur radio station he shares with his wife Janet.

The Zimmers, who have lived in Harvard almost 47 years, raised four children here before John turned his time and talent to the unusual project. One of the main reasons he built it, he said, was to share it not only with his grandchildren, but other schoolchildren as well. Zimmer visibly brightens when talking about the project with the reporter and the photographer, showing off the dam he constructed to regulate water flow into the waterwheel buckets, as well as the handmade bridge over the dam.

“I like to build everything,” he said.

The production of electricity has always fascinated Zimmer, he said in an interview Tuesday. “Every time you flip a switch, that means a turbine is spinning somewhere.” Before such modern technology, however, waterwheels were in common use to grind grain, pump water, and turn mechanical looms. They went out of favor in the late 1800s when modern electricity production came into widespread use. “That was the time of Edison,” he noted.

While Zimmer did some research on the history of waterwheels, there was remarkably little information about their actual construction. An Internet search for construction techniques yielded only one hit, from a man advertising plans for ornamental, small-scale waterwheels for gardens. It wasn’t exactly what he was looking for, Zimmer said, but he was able to scale the plans up to the eight-foot height that he wanted. “I wanted to get it as big as possible,” he said, because both the volume of water the waterwheel is able to carry as well as the difference in elevation are what determine the quantity of electricity produced. The hardest part of the project, he said, was connecting the motion of the waterwheel to the 12-volt generator that powers the radio station. He eventually succeeded, however, and has been able to call his former Raytheon colleagues on the ham radio using only waterwheel-produced power. Janet is also a licensed ham radio operator, he said. “So we still don’t have a need for a cellphone yet.”

Zimmer is looking forward to the spring thaw, he said, when the wheel will turn again. In the upcoming months he plans to share it with others who might have an interest in the project, as well as with his grandchildren. For now, though, he is content to view his handiwork from the back yard until the stream flows again in spring.