WowWee Rovio True Track Beacons

[Admin]

Anyone know how these Rovio 'true track beacons' work exactly? It appears to be related to the more expensive North Star sensor sold at acroname . . . if there was a way to easily hack them or make our own it could be pretty useful . . . a quick google search didn't reveal anything . . .

I did find http://www.northstartutorials.com/ but I only get a 'Bandwidth Limit Exceeded' error . . . also found this post that has a lot of clues.

At $300 (Rovio at Amazon.com) its a fairly cheap Wifi enabled North Star robot navigation system plus webcam that appears to be hackable.

[youtube]cpcYMNDYr-s[/youtube]

[youtube]q3Z69dVGVPw[/youtube]

[SciTech02]

I don't think anyone knows exactly how it works, except the people at Evolution Robotics (the same people that made/forgot about the ER1 robot).  They seem to be very tight-lipped about their technology: they just want you to use it and not wonder about how it works. 

That's pretty cool though, and the ability to use additional beacons to cover more rooms creates a fairly simple but powerful intelligent navigation system (I can see people filling their houses with those beacons, having them on every shelf  ).  It even has limited obstacle avoidance.  Personally, I can't wait when people start hacking them (I would like to see someone get Roborealm running on it  ).

[paulstreats]

Judging by the video, the fact that the table blocks the beacon signal as well as the signal being stronger nearer the center of the beacon - the true track beacons are just powerful i/r emitters. They work on the principle that most ceilings are painted white and so will reflect the i/r well when the beacons are pointed at them.

Some simple receivers on top of the robot can pick up the i/r light. Also, it can detect when its nearing the edge of the beacon because the amount of ir light will be less. - I would imagine that the emitters and detectors are encoded in some way aswell to stop cross interference and sunlight from creating false hot spots.

These beacons seem to be a reverse of the roomba beacons. The roomba beacons tell the roomba that its not allowed in that area wheras the ones for this robot tell it that its only allowed to operate within the beacon coverage area.

[MaltiK]

It could be a very long algorithm that measures the angle at which a light sensor onboard the robot reads the emitted light and robot will keep going straight until the angle is 0 degrees?. This could be a couple of amplified phototransistors? Maybe the same way a laser rangefinder works. Most likely I am wrong though because then the ceiling would have to mirror the lights back onto the robot at the very same light strength as when it first shot.

Check this out:

http://www.botmag.com/articles/scribbler.shtml
read part 2

[paulstreats]

The light would be weaker near the edge of the hot spot (inverse square law) So It can just judge the strength of the light. I really dont think there is anything too complicated going on

[Webbot]

Since there are 2 light beams then they will cause an interference pattern between each other. So the light intensity will vary not only by distance from the emitter but by the relative distance from the center of each emitter because of the interference pattern. When the distance from both emitters is an exact multiple of the wavelength then the intensity will be doubled. But when the wavelengths are 180 degrees out of phase the intensity will be zero.

Just a thought.

[Kalen]

so... waht wxactly is it for? [I'm new tot his, so help me out] I mean, Yeah it is a robot that knows where it is and can go charge itself at the push of a button, but what is it for?

[paulstreats]

You can book yourself a 5 minute test drive with a rovio here.
http://www.meetrovio.com/create-test-drive