iRobot Scooba Exposed: What's Inside This Robotic Maid
By Seth Fogie
Date: Jun 2, 2006
Imagine having your chores drastically reduced with the help of a robot. Seth Fogie details one such robot, iRobot's Scooba, and *literally* shows you the ins and outs of this incredible machine.
Robots have long fascinated humanity. Movies like "Artificial Intelligence: AI" (2001) and "I, Robot" (2004) portrait possible futures where all your mundane chores are performed by a mechanical life form. Just imagine not ever cleaning the windows, doing the dishes, or washing your car! On average, a family spends 1.8 hours per day doing just such activities. That is 12.6 hours a week, 655 hours a year, or 2,047 days of your life wasted on something that a robot could do.
While technology is several decades away from producing a fully automated cleaning robot, you can get a taste of the robot lifestyle today. In fact, the first robot cleaner was released in 2002 by a company named, ironically, iRobot. The Roomba is a self-contained "smart" vacuuming device that can be set up to automatically vacuum your carpets at a specified time, and then return to the charger after it has completed the job. In the last few years, the company has even opened up their programming interface to "hackers" who have managed to turn this device into their own customized multifunction toy.
The latest release (early 2006) from iRobot was the Scooba, which was created with your kitchen floor in mind. According to its website, the Scooba is "The first floor washing robot for the home that preps, washes, scrubs and dries your floor."
In this article, we are going to see just how this robot works, from the inside out. As you will see, trying to build a computerized robot that uses water is not a simple feat! Be sure to check out the iRobot site for an external shot of the Scooba that you can rotate and zoom.
Disassembly
In this section, we are going to outline the steps needed to take the Scooba apart for those brave enough or adventuresome enough to take "tech support" into their own hands. Please note that if you do this, your warranty will be voided. With that said, I noticed no obvious warranty detection stickers/components.
- First, remove all peripherals parts. This includes the scrubbing assembly,
filter, battery, water tank, and black suction hose. Figure
1 provides a shot of
all these parts removed (arrows point to original location).
Figure 1 Scooba’s peripheral parts.
- Next, flip over the Scooba (remove the tank first if you haven’t
already). Locate eight body screws and one longer screw in the scrubber assembly
area. You can also remove the wiper guide screw and front wheel (pull it out
gently), but this is not necessary to take the device apart. Figure
2 highlights
the screw locations (red).
Figure 2 Screw locations.
- Remove the two long screws located inside the front bumper, near the edge of the outer bumper. Figure 2 highlights their location (green).
- Flip the Scooba back over. Locate and remove the two screws near the center
of the device, and the two small Philips screws keeping the rocker arm assemble
in place. Finally, remove two located near the edge of the light blue section
(they are in deep holes). Figure
3 highlights the screw locations and the
details of the front of the Scooba.
Figure 3 Scooba front.
- Carefully lift off the top of the Scooba, paying special attention to the
ribbon connecting the two pieces together. Once the top is free, gently slide
the ribbon out of the connector on the top piece. The end of the ribbon is very
sensitive and can easily be damaged. Figure
4 shows a shot of the inside of the
Scooba with the ribbon still attached.
Figure 4 Scooba internals.
- If you want to disassemble the top piece, remove the four screws from top
piece that keep the light blue section connected. Keep an eye on the arms. They
will fall off. Next, remove two screws from the small dark blue moon sliver that
is holding circuit strip together, and crack open the piece to see the serial
port circuitry (Figure 5).
Figure 5 Serial port circuit board.
- To remove the bumper, unscrew the two support screws and two guide screws from the bumper assembly. They are located on either end of the bumper. You must remove both the support and guide screw to get the bumper off.
- To view the internal circuit board (Figure
6), locate and remove the three
screws that hold down the white plastic top. Be sure the surrounding area is
dry, and then peel off the white protective cover. It will stick a bit as there
is a water seal. You can pull out the circuit ribbon and the main sensor
connector to completely remove the white protector piece.
Figure 6 Main circuit board.
- The rest of the disassembly process is only necessary if you want to take
out pieces. To remove the fan, unscrew two small Phillips screws, keeping the
fan assembly in place. Then remove three screws with washers/separation guide
from the air/fan hose. Lift out the hose (it will take some force as the hose is
sealed to the body). Remove two screw/separator screws from brush motor assembly
(used to spin the scrubber). Remove the brush motor from the shell. Remove three
screw w/washers separator from fan/blower assembly. Figure
7 shows the Scooba
with all its main parts removed.
Figure 7 The Scooba disassembled.
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That’s it! At this point, you will have a Scooba that looks similar to Figure 7.
Key Parts
The following images provide a closer view of some of the key parts.
The Wheel
The Scooba wheels sometimes need to be replaced (because of normal wear and tear).. To do this, you must squeeze two latches and lift the wheel out of the Scooba shell. The entire wheel simply swings out far enough to unscrew it and for you install the replacement (Figure 8).
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Figure 8 Removing the wheel.
The Pump
One of the more amusing pieces of the Scooba is the pump. Figures 9 and 10 show this in detail. In short, the water is sucked into the pump from the tank, then pushed out through two hoses (one on either side) and sprayed on the floor.
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Figure 9 Front pump motor in detail.
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Figure 10 Rear pump input(bottom)/output(top) in detail.
Fan Assembly
The fan is probably the key to the success (or failure) of the Scooba. It provides the suction for the prep vacuum stage to suck up loose debris and existing water that is left over from a previous pass, and it also provides the suction for the post-scrubbing water retrieval feature of the Scooba. In other words, the Scooba is designed to use one fan for everything—if it doesn’t work, or there is a break in the suction, the Scooba fails. Figure 11 shows the fan in detail.
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Figure 11 Fan in detail.
How Does It Work?
The Scooba is loaded with little components that make sure everything works correctly. First, the bumper assembly actually contains three pieces of technology. The first is the sensor that sticks out above the rest of the device. This piece detects infrared light, which is emitted by the "Wall" included with the package. This helps to keep the Scooba in, or out of, a specific area.
Second, the bumper also houses the edge sensors, which are nothing more than infrared emitter/receivers that detect an edge when light is not reflected off the floor. There are three of these: one in the middle, and one on each side of the device.
Finally, the bumper also must detect when it hits a wall. This is done via small button switches that are located on either side of the Scooba. The rocker arms ensure any pressure on the bumper will be directed to one or both of these switches.
When the Scooba is turned on, it does a system check. This basically consists of making sure the tank, wheels, and scrubbing assembly are all in position. This is done via a series of magnets and detectors that are located throughout the device. Figure 12 shows you where a few of these sensors are located. As long as a magnet is near, the sensor will allow the Scooba to move.
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Figure 12 Sensor locations.
Once the Scooba does start moving, it checks the edge sensors and then starts moving in an outward circle, and finally takes off to find the closest wall/obstacle. All throughout this operation, the Scooba is monitoring the sensors to be sure nothing is wrong. If the water runs out or battery is too low, it will stop and beep to get your attention.
Negative Points
There are several problems with the Scooba. The following lists the issues I have noticed or learned about:
- The tanks sometimes leak, and always on the same side (left).
- The water pickup system is not really that great. You will probably have a wet floor when done.
- There are sensors to detect the cleaning solution (as I understand it). However, you can bypass this with vinegar.
- If you put the scrubber in the dishwasher, as early instructions suggest, your scrubber plastic will warp. This misleading advice has been taken out of the instructions.
- The darn thing will not work if any of the sensors detect something wrong. For example, the magnets sometimes fall out of the scrubber assembly. As a result, you would have to buy a whole new assembly to have an operating system.
- You must take great care of the device or it will die. This includes lots of cleaning and pampering.
However, I must point out that iRobot support is great (as I experienced it)! They are very quick to assist and help you out, including sending you a replacement device. Now I am not saying they will fix everything for free, but you should give them a call to find out what is wrong and if it is an established problem before kicking and/or beating your Scooba into submission.
Summary
The Scooba is the only robotic mopping system I have ever seen. It is the next step in an evolutionary process that will one day bring us the cooking/cleaning/shopping robot of the future. Even if you don’t want to take it apart, it is nice to hit a button and come home to a clean floor. However, if peeking under the hood of a device is SOP (standard operating procedure) for you, then the Scooba should keep you amused. At roughly $400, though, you might want to think twice before poking around its internals. One minor goof, and you will have yourself a rather expensive stepping stool.