dry spot
Will someone invent a smart lawn-watering robot that finds dry spots?
Q: Mike Jacobellis, via email, asked: "I Wish Someone Would Invent A Lawn-watering roomba that sees dead spots." A: Soon, you may be able to plant a few sensors, no robot necessary. Engineer Jim Canyon's prototype measures the soil's ability to store electric energy. Higher numbers mean wetter soil, since water stores energy well. Once you know the moisture levels of your yard's soil, says Canyon, you can design a sprinkler system to water only the thirsty parts.