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iRobot Roomba 780 was released in 2011, yet it remains a popular choice for those wanting to buy a robotic cleaner. It is a quite affordable robot with many capabilities under the hood. Let’s take a look at Roomba 780 and decide whether it’s worth buying now, 6 years past its release date, or you should better buy another robotic cleaner.
NOTICE: This robotic cleaner was already used before we got a chance to review it. Its chassis has some slight scratches, and there are small stains of unidentified material on the plastic surface. Other than that, this Roomba 780 unit is perfectly fine.
The robot is almost circular in shape.
A bevel from the edge to the bottom helps Roomba 780 traverse various obstacles, while the small angularity on the top lowers the possibility of your vacuum hanging under the obstacles with small gap.
The chassis is made of black matted plastic. Large circular part of the upper panel has gray-silver surface with flat, somewhat damage-resistant coating. The circle is fringed with details made with the same plastic. The center contains piece of dark semi-transparent plastic protecting the LED indicators (touch button labels, battery charge label, segmented clock indicator, etc.)
A circular button with mirror-smooth chrome plated surface can be located in the very center of the upper panel. Its bezel, sign and label is lighted with LED indicators, which color can change from green to red depending on battery status. Reclining handle on the top helps carry the device. It hides a service slot covered with rubber cap. Bottom part of bumper is fringed with rubber cap, while the upper part is covered with transparent black plastic that would help the device receive IR signals.
On the upper part of the central bumper is the upward-looking IR sighting sensor. It detects the height of clearance under furniture and helps robot decide whether it can clean under that piece of furniture. If we turn the vacuum upside down, we’ll see two contact areas, bow thruster, side brush, battery compartment cap, two steering wheels on spring levers, gray compartment with main brushes and transparent bottom of removable dust collectors. Six height shift IR sensors are located on the perimeter, closer to the edge of robot.
Charging base is outfitted with external PSU. It makes the base lightweight and portable. (Length of removable power cable equals to 100 cm, PSU cable – 95 cm).
Small rubber area and larger porous plastic area are glued to the bottom of the base. However, it’s still very easy to accidentally move the base. Even though the vacuum handles the base pretty carefully, it will be a good idea to glue the base to the floor with two-sided tape. Or you can simply place the base in the corner and make sure the robot can reach it without troubles. There are two advantages of external PSU: first, it will be much easier to repair the PSU in case of its failure; second, you can charge the robot directly from the PSU. There’s even a special port on the chassis. However, there are at least two significant drawbacks: the base is lighter (see above) and you’ll have to place both the base and PSU on the floor, which can be aesthetically challenging.
The vacuum is supplied with an IR remote control and two navigational devices. In additional, standard package includes a set of reserve brushes, filters and two brush cleaners.
Now to the documents. They include limited warranty disclaimer, short user’s manual, instruction DVDs and PDFs of full user’s manual. The vacuum is packed into a relatively large box with plastic handle.
Axes of steering wheels are located on the same diameter of chassis circumference. This kinematic scheme allows the robot to spin around without changing borders, leading to exceptionally good maneuverability. Large steering wheels diameter (71 mm) and 30 mm hinge stroke in wheel centers allows the robot to traverse small obstacles easily. It can potentially bypass obstacles with height of up to 20 mm.
The upper brush moves the trash closer to the center during the cleaning. Its axis is tilted inwards, providing stronger pressure during “from side to forward” movement. One notable thing is the construction of the side brush – its elastic leads end with relatively firm straight bristle. It helps the brush work effectively without losing its shape.
Two main brushes move towards each other. First the rubber scraper brush moves the large trash, then the second brush with scrape and bristle takes large and small trash and throws it to the dust collector. Inertial movement of trash is complimented with airflow that comes through the rotating brushes and two HEPA filters, stopping small trash.
Dust collector bottom is made of transparent plastic, but it’s not especially useful. You’ll have to turn the robot upside down to see whether it’s full. Luckily, it’s quite easy to clean: just recline the shade and throw away the trash.
Two HEPA filters in yellow cases can be removed and cleaned as well.
The air ventilator is built in the dust collector case, and as a result, you can’t wash the dust collector. The removal procedure is quite convenient and after a tiny bit of training you can even do it with one hand, without moving the vacuum. The air is blown away through the grate on the back wall of the dust collector.
Main brush compartment is fixed to the hinge. It follows the floor relief with a 9 mm step (approximately), slipping on wire guides. Scraper brush protrudes beyond the guides for 1,5 – 2 mm, while the bristle of the second brush protrudes for 2 – 3 mm. It provides optimal work efficiency on uneven surfaces with virtually any surface. Brushes can be detached from the compartment for cleaning. Bristle brush can be cleaned with supplied tool (ring with small gears). The second tool will be helpful with removing coiled threads and hair. You can remove face caps with bronze bearings for more thorough cleaning. However, you’ll only need to clean the caps of first scraper brush, as hair and other long fibers can sometimes get coiled there.
You can buy additional air filters, main and side brushes, and other wearable parts, including the battery.
You can replace the battery yourself. The only thing you’ll need is middle size crosshead screwdriver. You can find the full list of accessories and expendable materials on the manufacturer website.
The vacuum CANNOT be used in humid buildings or on surfaces with spilled liquids. Violation of this rule may result in severe malfunction.
iRobot Roomba 780 has three main cleaning modes:
- Automatic cleaning of all available area: The robot will clean all available areas and return to base station;
- Spot mode: Intensive cleaning of user-chosen area. You will have to direct the robot to the spot with the RC. The robot will remain in initial position after cleaning;
- Manual cleaning.
All modes can be launched by pressing the corresponding button on the chassis or the RC: CLEAN will launch automatic cleaning, SPOT will launch intensive cleaning mode. Pressing DOCK will force the robot to return to base station. You can schedule the automatic cleaning for any time at any day of week. If you created a schedule, the robot will clean the area at the scheduled time and return to base.
Remote control allows you direct the movement (and cleaning) pattern of robot. There are five movement commands: move forward, turn left or right, strife left or right. The robot will only move if the corresponding button is pressed. If facing an obstacle, the vacuum will automatically evade it. It will also automatically dock to the base when near it.
Additional navigational devices will help organize your cleaning. They work from two LR14 power elements (also compatible with C, A343 or saline batteries). They can function in two modes: Virtual Wall or Lighthouse. First option will emit a IR ray that would prevent the robot from moving. It is usable for creating areas where it is not advisable to clean. Lighthouse mode will help you create a cleaning sequence: when the robot is inside the area with Lighthouse, it will not leave it until it is completely cleaned. Operational mode and barrier length are selected with switches on the devices. They will activate automatically when the robot goes online and shut down once it returns to the docking bay.
The robot informs the user about its status with LED indicators. In addition, it plays a short tune when changing modes. If an error occurs, it plays a voice message with error details. You cannot disable the notifications.
We used the robot to clean our testing area. It took around 20 – 30 minutes for the robot to clean the testing area and return to docking bay. More than 90% of trash is collected during the first run. The only uncleaned area was a 40 cm circle around the docking bay.
The robot does not clean areas around the base, and we think it’s quite good. At least it won’t move the base during cleaning. It has also skipped some small areas in angles where it can’t get in or move trash with its side brush.
We can assume that the robot assesses the cleaning area by, for example, average distance from obstacle to obstacle and determines the time needed to clean the area. In our case this time is close to optimal, as additional cleaning will not yield higher efficiency rate. The robot seems to be unable to solve the long-range navigational tasks, but it can easily decide where to move next and how to get out of complex spots and wires. IR proximity sensors, mechanic bumper and movement tracking with optical sensor help the robot do its work.
Judging by how the robot moves during cleaning, it picks several movement options depending on current status, some kind of history and randomness factor. We have identified three variants, but there might be more:
- #1: The robot moves from obstacle to obstacle with subsequent direction change. It is used to move from room to room and, possibly, to assess the available area;
- #2: Fan-shaped movement with return to initial position. Used for intensive cleaning of heavily contaminated places. The robot seems to use information from ultrasonic dirt sensor located in the brush compartment and optical sensor located before the dust collector;
- #3: The robot traverses obstacles clockwise and moves along the wall on a small distance from the obstacle until IR proximity sensor detects something. It is used to clean around chair legs and along the walls.
The robot cleans the area regardless of movement option. It rotates main and side brushes and runs the air with ventilator.
Narrow paddock (5 cm wider than the robot chassis) wasn’t a problem for Roomba 780. The robot easily got inside it during the first run and easily got outside after completing his job.
The robot has always docked to the docking bay in first attempt.
Multiple launches of cleaning cycle until full battery discharge allowed for very high garbage collection rate, and the robot worked for almost an hour. It takes the same time to fully charge the battery. However, we must note that our testing example must have had a miscalibrated battery, as the robot suddenly stopped and notified us that we should charge the battery instead of returning to docking bay itself. We assume that the robot will work much faster and return to the docking bay on its own after changing the battery, but the charging cycle will most definitely take more time.
When the robot starts charging, the base will take around 26-27 W. The power consumption then drops to 4,3 W. The docking bay itself consumes around 1,2 W.
iRobot Roomba is definitely a solid purchase. It is a very advanced cleaning robot that would ease your life significantly. However, there is one moment.
If you’ve already read our iRobot Roomba 880 review, you might’ve noticed that there are almost no differences between Roomba 780 and 880, except for better battery life, more solid docking bay and somewhat better cleaning technologies. Both models have already aged (Roomba 780 was released in 2011, Roomba 880 – in 2013), and there are a lot of discounted or used vacuums on sale right now. If you’re ready to spare a few extra bucks, why shouldn’t you look for Roomba 880? It is newer and more comfortable to use.
- High cleaning quality, including along the walls and near obstacles;
- Scheduled cleaning mode;
- Nice packaging, including RC, navigational devices and reserve details;
- Voice notifications.
- High noise levels;
- No “clean until full power drain” mode.