iRobot runs afoul of astronomers over proposed mower

Radio astronomers try to close the door on iRobot's wireless mower ambitions. Here's what it means for your lawn.

There's a robot lawn mower saga in the offing at the FCC, and the outcome may have a big impact on the future of automated lawn care in the U.S. In January, iRobot requested an FCC waiver to a rule that "prohibits the use of fixed wireless infrastructure, in order to obtain equipment certification for and market a robotic lawn mower." On March 6, the National Radio Astronomy Observatory (NRAO) filed comments with the FCC objecting to the waiver. Here's the issue:

NRAO's Green Bank Telescope

The NRAO operates three radio telescopes in the U.S. that listen to the heavens, observing frequencies around 6.7 GHz (the NRAO also operates the Atacama Large Millimeter/submillimeter Array in Chile, the most complex telescope ever built). One of these observatories, the Green Bank Telescope in West Virginia, is surrounded by one of the few "quiet zones" for radio transmissions in the country. The area around the town of Green Bank has strict prohibitions in place to prevent signal interference, which has made it a safe haven for purported sufferers of electromagnetic hypersensitivity. Clearly the NRAO takes its signal interference seriously.

iRobot is requesting permission to certify a device that uses radio beacons arranged in a perimeter around a lawn. The staked beacons would communicate with the lawn mower in the 6240 - 6740 MHz band, which is well-suited to short-distance radio applications. In its objection, the NRAO notes that the FCC rule governing allocation of ultra-wideband (UWB) spectrum 5972 - 6700 MHz requires that "all practicable steps shall be taken to protect the radio astronomy service from harmful interference." The NRAO believes that the beacons would constitute a "fixed outdoor structure," which is explicitly banned under the FCC's Part 15 rules. But iRobot maintains "the use of the portable beacons is consistent with the intent of the rule because it does not establish a wide area communications system or network."

Here's why this is important for the lawn mowing masses. Today's robot lawn mowers require guide wires, a huge barrier to the technology gaining a toehold in the U.S. A wire along the perimeter of a lawn forms an electronic fence that pens commercial robots mowers in. Without it, a machine would break loose like a bronco on a tear. The wires, which are typically buried under the soil, require a fair amount of setup and are difficult to arrange in a way that allows mowers to properly clip edges and corners. They can also break with an errant shovel strike, which means cumbersome repairs or replacement.

Except for grass. Photo courtesy of iRobot.
Robot lawn mowers have caught hold in Europe, however, where small lawns and the high cost of manual labor make them attractive alternatives to hand mowing. Lawns in the U.S. are bigger. There's also a large labor pool of low-wage landscapers in this country, jobs often filled by immigrants. It's an interesting case of human labor keeping robots out of a job.

In order for iRobot to entice U.S. consumers, it needs another "no duh" device like the Roomba, something robust, intuitive, and above all simple to use. Getting rid of the wire is the critical step. It's unlikely that the NRAO's objection will ultimately derail the company's ambition, but it may slow it down as FCC regulators decide whether to grant an allowance. Any such provision may also come with conditions aimed at keeping the area around Green Bank quiet.


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