My lawn is a solar collector. Energy is stored in the plant material, and it can be harvested after the lawn is mowed by firing the clippings in a combustor to generate heat or power. A more efficient use of this energy, however, is to recycle the clippings back into the lawn or into a garden as compost to offset petroleum-based fertilizer.
Perhaps the most environmentally benign option would have been a manual reel mower. However, I wanted to be able to mulch the clippings or collect them for composting as I desired. Plus, my reading suggested that manual reel mowers don’t handle weeds well, and my lawn has a pretty serious weed problem.
When I was a kid, one of my household chores was mowing the lawn with our gas mower. I remember jerking on the starter cord a dozen times to get the engine to turn over, inhaling exhaust fumes, being deafened by the engine roar, and having my hands vibrated so severely that I couldn’t feel my fingers. I also remember running out of gas and having to fill up the mower from the fuel can we kept in the garage. I hated mowing the lawn.
The cordless mower is a totally different experience. It is quiet and smooth. The engine easily turns on and off with a spring-actuated lever – no starter chord. At 76 pounds, the CMM1200 is a bit heavier than push gas mowers in its class (which usually run under 70 pounds) due to its 24-volt battery. However, it cuts grass just as well as its fossil-fuel-fired cousins, and frankly I need the exercise.
Of course, so long as the mower is recharging from a wall outlet, it is not truly using renewable energy. However, what sets cordless electric mowers apart from their plug-in counterparts is that the recharging station can be modified to use any electricity source, including solar power. Thus, as a long-term project, I plan to build a solar-powered charging station to make my cordless electric mower truly renewable. However, I will probably wait until the manufacturer’s warranty expires before attempting such a retrofit.
One way to keep a Formula One racing team moving at breakneck speed in the pit and at the test facility is to bring CAD drawings of the racing vehicleís parts down to the test facility and even out to the track.
Most of us would just as soon step on a cockroach rather than study it, but thatís just what researchers at UC Berkeley did in the pursuit of building small, nimble robots suitable for disaster-recovery and search-and-rescue missions.
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