Dust sensors, the latest CES vacuum cleaners, and the Internet of Things

The Roomba 770 is a polished product, as would be expected for a robotic vacuum that is now several generation models old. For those familiar with older Roombas, the major improvement (other than much better battery life) is the addition of a second dirt detector The older Roombas have an ultrasonic (acoustic) dirt detector for years; the 770 adds an optical dirt sensor as well. Other very noticeable changes are optical sensors (the Roomba can now ‘see’ walls and other obstructions, unless they are black in color) that allows the Roomba to slow down and do a soft touch with walls compared against the older Roomba models. Asside from adding a HEPA filter that is better for people “with pets and allergies”, another major change is that the Roomba will now do a more human-like back-and-forth pattern when it detects carpet dirt (the older Roombas would go into a circular spot cleaning mode when they detected dirt). The 770 also has virtual wall units that now turn themselves on automatically (older units only turned themselves off automatically).

Why dust/dirt sensors are very important for robotic vacuums

The dirt sensor is very important. On a clean, frequently vacuumed carpet, a human basically can’t detect that some regions (where there are heavy footballs, or near windows and doors where air currents deposit pollution dirt). The Roomba, however, can detect this additional dirt, and focuses its time on those areas in need of the greatest vacuuming. It gets the carpets cleaner than most humans will. (Every cleaning service we’ve every tried does a single pass and then says “we’re done.” But even on a clean carpet, a single pass is not enough. The Roomba does multiple passes, and extra passes on top of that where it detects extra dirt.) Typically the Roomba will get the carpet a (barely perceptible but very real) shade lighter, even on a heavily (weekly) vacuumed carpet, which is amazing as we typically don’t see this with manual single-pass cleaning!

Vacuums as both a potential cause of and solution to airborne pollution and allergies

(Incidentally, the EPA recommends a carpet cleaning schedule to minimize dust being given up carpets. Since this schedule is on the order of weeks or months, we’ll assume most readers are vacuuming much more frequently than this, and we’ll hold this topic off for a future post.)

Ironically, the 770, when it is running, will send PM2.5 and PM10 dust particle counts spiking in the air. (We say this is ironic, because the 770 adds a HEPA dust filter and is marketed for “pets and allergies.) The increase is modest compared with running a dishwasher, gas range, or shower, but it’s still there. (It took our room from “excellent” to merely “good” on the unofficial, stricter indoor air quality standard reported by our app that some people use. Both counts were still in the EPA “good” range, but some people can notice the difference.) The irony, of course, is that if the room is not vacuumed, footfalls will eventually stir up more dirt, so of course this robotic vacuum is an invaluable tool in improving air quality. Yes if you have allergies or asthma you’ll probably want to vacuum frequently, maybe with this HEPA filter robot vacuum when you’re not around to breathe in the dust it stirs up!

iRobot Roomba 770 versus Roomba 780

Our 770 also includes a dust bin sensor that reports when the dust bin is full. iRobot kept the Roomba’s navigation system simple. It uses several simple patterns to insure multiple passes over a room. One downside of this robust simplicity, however, is that larger rooms will take longer for the Roomba to vacuum and ensure every area has been vacuumed several times. The more expensive 780 model solves this problem by adding ‘virtual lighthouses.’ These are similar to virtual wall units, except that divide the area into several virtual rooms. This allows Roomba to more efficiently navigate each virtual room (since it similar than the complete area to be cleaned) and throughly clean it before moving on to the next virtual room. If you have a large area to vacuum, the 780 might make sense because of its room lighthouse feature. Then again, a small amount of preparation is typically required for each room (e.g., moving loose cords out of the way), so if you’re around while the Roomba is vacuuming you could simply use a virtual wall unit to cordon off a small area, and manually move the Roomba to the next ‘room’ when it is done with the first one.

iRobot Roomba versus iRobot Scooba; Scooba for countertops?!?

While we’re on the topic of robotic vacuums, we’ve also tested a iRobot Scooba 230, which we’ve found saves us time in washing floors and countertops. (Washing countertops is a bit of an off-label use for the Scooba, but it works.)

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