Evolution Robotics Answers Your Questions About Mint
Writing by Evan Ackerman on Thursday, 14 of October , 2010 at 2:22 am
Remember all those questions you had about Mint? Well, we now have answers. Answers part one, anyway. Tomorrow, we’ll be posting an interview with Evolution Robotics president and CEO Dr. Paolo Pirjanian, where we’ll be talking about the history of Mint, as well as what Evolution Robotics is planning for the future. But today, we have answers to some of your more specific questions about Mint, from Mike Dooley, the vice president of product development at Evolution Robotics.
-Why did you decide not to include an automatic charging system?
We gave serious consideration to having a self-charging dock, and with NorthStar already on board to guide Mint back home, it was tempting to add (folks may recall that Rovio already uses NorthStar to self-dock). Ultimately we decided to go without one based on feedback from consumers.
The most common comment was that when Mint was done cleaning, they’d prefer just to put it away – just like they would their mop. For many, having a robot and a charging dock sitting out on the floor all of the time added more clutter to the room, even though Mint is pretty styling! :) So, we worked with the Fuse Project to give Mint a very slim vertical footprint, making it easy to tuck away by standing it on its end.
We were also not sure how much time and effort a self-charging dock would really save. As you mentioned in your review, other “automated” robots aren’t fully automatic. With robotic vacuums that self-charge, you still have to empty the bin and do things like check the brush. Instead, we looked at the total user experience, and how to make it as seamless as possible. That led us to things like making it super-easy to change the cloth, with features like the magnetic pad and zip-to-lock grip strips.
Lots more on carpet detection, Rovio beacons, the NorthStar system, and hacking, after the jump.
-We had a few minor issues with Mint getting on low carpets; how exactly is Mint programmed to avoid carpets and area rugs? What is the maximum obstacle height or drop that Mint will attempt to traverse?
Mint won’t go over an obstacle that is over 1 cm in height (and usually less depending on the situation). There are floor sensors built into the front cleaning pad, which let Mint literally feel the surface of the floor through the cleaning cloth. These sensors work in two ways, detecting if the floor surface drops away (like at the top edge of the stairs) but also if Mint’s pad starts to ride up onto another raised surface (such as an area rug or transition to carpeting). The same sensors help Mint avoid cords and other low obstacles.
Because not everyone has perfectly smooth or even floors in their homes, we set the floor sensors to purposely ignore small changes in the floor surface. This is particularly important for homes with uneven tile floors or that have slight transitions between one hard surface floor and another. This trade-off means that Mint can drive onto to some very thin rugs (like kitchen mats), as well as some cases of carpeting where its flush with the hard surface floor next it and there is no transition strip. For most users, this doesn’t seem to be an issue, e.g. if they have a very thin mat, they are ok with moving it to let Mint clean the floor. But like with a lot of other features, we are looking at ways to make Mint handle more cases automatically.
-We’ve had a lot of questions about the NorthStar system. Can you elaborate on how it works, what environmental factors effect it (such as weird ceilings or large tables which obstruct Mint’s view of the ceiling), and how it can be used to enable Mint to clean multiple rooms?
NorthStar works a lot like the navigation system on your car. However, instead of tracking signals from satellites, we use the NorthStar Cube to project IR spots onto the ceiling. These signals create a micro-GPS type system inside the room and provide Mint a “global” reference point for its position.
Based on how we have designed the system, things like having an angled ceiling or even light fixtures and vents on the ceiling don’t have much of an impact on the signal. In addition to the NorthStar signal, there are other “local” positioning sensors onboard Mint that track its relative motion. The readings from all of these sources are fused together to map Mint’s position as it cleans, along with the location of walls and obstacles.
Because Mint has multiple inputs to the map, it doesn’t need a continuous view of the NorthStar signal. Mint can go under tables and beds, and even outside the room for extended periods of time, and still track its position… Just as if you drive your car into a tunnel and your GPS still projects the estimate of your position. Mint does need come up for air every so often to re-check its position relative to the NorthStar signal. Usually it does this in the background, but you can see the case specifically when its cleaning into a room outside of where the Cube is located. After a while of cleaning out of range of NorthStar, the three blue dots on the front of Mint will start to go down to two dots and then to one dot, and if needed, Mint will drive back towards the Cube to double check where it is, recalibrate the map, and then resume cleaning where it left off.
-Does Mint recognize Rovio beacons? If so, can you use them to extend Mint’s range? If not, would they interfere with Mint?
The short answer is that Mint will recognize the Rovio room beacon (the one with room ID the switch on the back), but it works differently than Rovio in terms of dealing with multiple beacons.
With the advancements in Mint, one NorthStar Cube can cover up to 1000 square feet of cleaning. By contrast, Rovio would have needed multiple beacons to navigate across that much area.
Because Mint’s cleaning area is so large and people may only want to clean one area of their house at a time, we decided to limit Mint to using one Cube per cleaning session. When you start Mint, it scans for the NorthStar signal, locks on to the strongest signal, and cleans that specific area of the house. If it comes across other NorthStar frequencies in range of the first signal, Mint will ignore those. You can purchase additional NorthStar Cubes with different frequencies. This lets you cover two areas of your home without needing to move one Cube to a new area each time your clean, but Mint will still stay in the zone where it was first started.
Mint will recognize the room beacon that was sold as an accessory for Rovio. If it is the strongest signal, Mint will lock onto that beacon and use it for cleaning just as if it were a NorthStar Cube. Likewise, Rovio will recognize Mint’s NorthStar Cubes. Note that Mint will ignore Rovio’s base-station beacon, since that was specifically allocated for Rovio for docking.
-Is Mint hackable, or do you currently have any plans to make Mint accessible to hardware or software modification?
We definitely understand that the technology inside Mint is exciting, and there are things we haven’t shown yet of what it can do. At the same time, we see Mint first as a consumer appliance, and our mission is to make it the best possible product experience for consumers. For now, we’re putting all of our energy into the product, and do not have any plans yet for opening up Mint more than what’s already there.
We are interested to see what the development community (hackers) do with Mint on their own, and then will see what would be a good next step.
-Do you have any pictures of what’s inside Mint and the NorthStar cube?
We do, but it looks much more pretty on the outside. :)
Again, would be great to see someone in the community opening it up and getting the discussion going of how it works.
-Why’s it called “Mint?”
It’s named Mint in reference to keeping your floors in “Mint” condition.
So, there you have it: Mint officially wants you to rip one of their robots open and show us all what’s inside… And when you do, send me pics. I’d do it myself, but I doubt they’d take kindly to me eviscerating their review unit.
Many thanks to Mike Dooley and Stephan West for answering our questions.
[ Evolution Robotics ]
[ Mint ]
Comments (2)
Category: Consumer
- Add this post to
- Del.icio.us -
- Digg
Comment by ivoidwarranty
Made Thursday, 14 of October , 2010 at 9:53 am
Thanks for getting an answer on my question regarding if the NorthStar system works with “weird” ceilings!
Comment by home office furniture
Made Monday, 21 of November , 2011 at 7:27 am
Hey all, I was simply checking out this blog and I actually admire the basis of the article, very nice work.
