Slashdot Log In
Lego Segway
Posted by
michael
on Thu Oct 17, 2002 09:35 PM
from the balancing-act dept.
from the balancing-act dept.
Jeff Lalo writes "This Guy has built a Lego version of Dean Kamens Segway Human Transporter. This thing was constructed using only Legos, two cheap (~$40) custom sensors and some smart programing using the open source BrickOS for the Lego RCX. The LegWay, as the creator calls it, can balance itself on two wheels and follow a line. Pretty cool for few lego blocks!"
This discussion has been archived.
No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Ahh, the joys of Lego. (Score:5, Funny)
Not as cool as... (Score:3, Interesting)
Url, anyone? I sadly never bookmarked it (shame on me). It'll be good for me, good for your karma, good for everyone.
Re:Not as cool as... (Score:5, Interesting)
Parent
MP5 is a gun? (Score:3, Funny)
Re:Not as cool as... (Score:5, Funny)
Parent
Re:Not as cool as... a Playable Harpsichord! (Score:5, Interesting)
Parent
Re:Not as cool as... (Score:3, Funny)
Boredom (Score:3, Funny)
First post?, and he's prepared for slashdotting (Score:5, Informative)
Smart man... (Score:5, Informative)
Anyway... IF the Geocities mirror list get's slashdotted, here are the list of mirrors:
http://perso.freelug.org/legway/LegWay.html [freelug.org]
http://legway.armorica.biz [armorica.biz]
http://home1.gte.net/res1g289/StevesLegWay.htm [gte.net]
And I can't get up!!! (Score:5, Interesting)
Until or unless it's articulated, this will always be true. Segway can't right itself from this position either...?
Re:And I can't get up!!! (Score:5, Interesting)
IANAPH, but I think it is possible.
It might seem that because the center of mass is below the axles, that you could not lift the chassis by taking off in one direction, then reversing.
But, if the wheels are big enough, the angular momentum built up could do it.
You could even do it without lateral movement. Imagine this:
Segway thingy is lying down:
O--
Segway thingy pops up a little kickstand:
Q--
Segway thingy starts whirring its wheels counter-clockwise:
Q-- (imagine the whirring part)
Segway thingy reverses it's engine, causing the -- part to react and rotate counter-clockwise.
|
|
Q
Drop the kickstand (quickly), and off you go..
-These are not the sig your looking for...
Se
Imagine a little
Parent
Re:slow down (Score:3, Interesting)
The easy idea would be to place some sort of hemisphere on the outside rims of the wheels so that an unattached wheel would roll to its side. You'd also have to place some extension to the left and right at the top to prevent the unit from lying flat. As long as only one edge of the tire gripped the ground, rotating the tire at high speed in one direction or another should (messily) jerk/flip the unit in a position from which it can recover. (It should be less force than a fall at any rate)
The final piece of the puzzle would be to add some type of sensor that allows you to discern your angular orientation with respect to the ground. One or more accelerometers would be sufficient for this.
~GoRK
Sad But True (Score:5, Funny)
I give him about 2 days before being slapped with a lawsuit for patent infringement. And then Lego towns all across the Midwest will pass laws preventing them from riding on sidewalks (at the behest of Ford, GM, and Daimler-Chrysler).
A geocities link? (Score:3, Funny)
SLASHDOT.
FRONT PAGE.
Hahahahahahahahaha!
Seriously. I bet no more than 150 people got to actually see that site.
Better in a few ways... (Score:3, Funny)
Just what we need (Score:5, Funny)
And I thought I was proud of my lego castle greyskull all those years ago!
Re:Just what we need (Score:3, Funny)
Mirror (Score:4, Informative)
now that's ambitious... (Score:3, Funny)
8 inches tall? (Score:5, Insightful)
Oh sure, I find out NOW... (Score:5, Funny)
Amazon.com
customerservice@amazon.com
Dear Sir/Madam:
I regret to inform you that I must cancel my current reservation for the Segway [amazon.com], currently listed at $7999.95 (US).
I would like to place another order for the following items now:
- Three MindStorms Lego Robot Kits [amazon.com], version 2.0, at $24.95 each
- One copy of How To Build a Segway Human Transporter for only Fifty Dollars [amazon.com] (O'Reilly Press) at $69.95
- One Flux Capacitor [amazon.com] at $499.95
I trust that a credit to my account will be arranged.Thank you in advance for your prompt action in this matter.
Sincerely,
Saint Aardvark the Carpeted
Re:Oh sure, I find out NOW... (Score:5, Funny)
Parent
Re:Oh sure, I find out NOW... (Score:4, Informative)
?!?!???!?!
They're actually $200 each.
Parent
Re:Oh sure, I find out NOW... (Score:5, Funny)
My buddy John can get one for you.
Parent
Re:Oh sure, I find out NOW... (Score:5, Funny)
Parent
Geocities links (Score:3, Interesting)
geocities *always* hits data limits.
That's good work (Score:5, Interesting)
woooaa (Score:3, Interesting)
The Mailing list (Score:3, Informative)
segway vs. legway (Score:5, Interesting)
Re:segway vs. legway (Score:4, Insightful)
The segway is a great gee-whiz high-tech toy, but that doesn't necessarily make it practical for more than a couple different applications and it certainly isn't the fix-all DeKa would have the public believe.
Parent
Interesting OT: Segway is not IT (Score:5, Interesting)
"Robert Metcalfe, the co-inventor of the Ethernet office networking standard, who is a friend of Mr. Kamen, told me via e- mail: 'Some months ago when speculation was running high, I said that Kamen's It was more important than the Internet, but not as important as cold fusion, had cold fusion worked out. The It I was talking about, which I did not disclose, was NOT Segway. That's all I can say.'"
To the /. editors (Score:4, Interesting)
In the article submissions form, put a little check box titled "Slashdot can mirror locally" or some other phraseology.
Then provide the original link like you normally would, but on the last line where it says "Read More | XX of YY comments" add another link that says "Slashdot Article Mirror"
Re:To the /. editors (Score:3, Insightful)
Re:To the /. editors (Score:3, Insightful)
Re:To the /. editors (Score:4, Insightful)
Perhaps make the "cache" portion of the submission perl script check robots.txt, so site admins can forbid slashdot to archive an article..
-gleam
Parent
Meantime, from AARP... (Score:5, Funny)
"Lego was meant for the rumpus room, not the sidewalk!", complained an unidentified senior.
Another protested, "Hey! The sidewalks are already dangerous enough what with those dang newfangled bicycles! If you add Lego Segways, I could get killed!"
Among the signs noted at the protest was one proclaiming, "Lego Segways at 11 MPH will injure me!"
Suggestion for Slashdot Admins (Score:5, Insightful)
I really think this is starting to become a problem for people doing really cool stuff who don't have the money for a really good webserver. If slashdot thinks that a 20MB site is cool enough to post, surely Slashdot has that 20 MB of space on the its webserver to donate for a limited time. This would ensure that people like me can get to the site and people who do the cool shit aren't punished for doing cool shit.
SetupWeasel
Re:Suggestion for Slashdot Admins (Score:5, Informative)
Parent
Re:Because it will get /.ed [formatted] (Score:4, Informative)
This LEGO robot was built to stand on two wheels and balance, follow a black line, and/or spin in place.
LegWay Program
The program for LegWay was written in BrickOS (LegOS) and uses EOPDs to maintain a constant distance to the ground. As the distance decreases, LegWay moves forward. As the distance increases, LegWay moves backward.
Every 50 ms, LegWay attempts to re-calculate the balance point by measuring the current distance and motor speed.
To move forward (for line following) LegWay actually sets the motors to run backward, causing a tilt, which it automaticly corrects, by moving forward. When one sensor is over the line, it stops that motor, and LegWay balances using only the other motor, causing it to turn.
To spin in place, both motors are shifted "off center" in opposite directions, the same amount, but they still correct for tilting.
In the pictures, you may notice the second sensor is disconnected. The main LegWay program will follow a line if two sensors are attached (always moving forward) or attempt to stand still, if only one sensor is attached.
If the motors are set at full power (either direction) for more than 1 second, LegWay assumes it has fallen over and the program ends.
LegWay EOPD SENSORS
LegWay uses two EOPDs (Electro-Optical Proximity Detector) from HiTechnic Sensors to balance and detect lines.
The EOPDs are based on the IRPD (Infrared Proximity Detector) circuit, but use visible light to determine distance by checking the detector, sending a pulse of light, and checking the detector again to calculate the amount of light reflected. The value returned will change based on the distance to an object AND the color of the object. IRPDs can be used in place of the EOPDs, but they will not work as well for detecting/following lines ** I'm told these sensors will cost the same as the IRPD sensors, and will be available in a couple weeks (November 1)
For this application, a small change in the value will usually indicate a change in the distance to the surface, while a large change will represent a change in the surface color (white to black) The EOPDs usually do not return a usable distance to a black surface, because the light is absorbed.
LegWay VIDEOS
Here are a couple videos, and some more pictures. The videos were taken with my LEGO Vision Command camera, so they're not really the best quality. I don't know my bandwidth limit, so if the videos don't work, try back later.
Brickshelf Pictures
LegWay Following a Line
LegWay Spinning This video really doesn't show how fast it's going. The motors are at full speed (almost) and in this video, it doesn't change direction.
Legway Building instructions
LegWay Past
I attempted to build LegWay using an accelerometer to detect tilt, but soon realized the acceleration due to gravity would not change as the robot tilts, because the robot is accelerating at 9.8 ft/sec?(physics was a long time ago). So the reading will be zero, until it smashes into the floor.
Several people have said they tried (without success) to build something like this with standard LEGO light sensors, but I don't believe they have the resolution required. (not even close)
LegWay Future
My next project will be to make LegWay work with a remote control. I have a couple ideas, which include using a SpyBot remote to drive LegWay around, or use a regular LEGO remote to run some pre-programmed moves.
Another idea is to make LegWay stand up (from a lying position) on it's own. It can't do that right now, because the center of mass is below the axle when it on it's side.
Thanks for checking it out. Feel free to tell me what you think.
Steve
e-mail:hassenplug@mail.com
Parent
Re:wait (Score:3, Funny)
He's a wise man (Score:5, Funny)
RMN
~~~
Parent
Re:Impossible (Score:3, Insightful)
In fact, I think there are about six billion of 'em... and you're one of them.
Re:Impossible (Score:5, Informative)
Parent
Re:Impossible (Score:4, Insightful)
Counter-proof: You only have 2 eyes, yet you can.
Parent
Re:Impossible (Score:3, Insightful)
Or for a less destructive method just try walking around with you eyes close and notice that you actually don't need them to move. They do help on collision advoidance but beyond that they are basically useless.
Re:Impossible (Score:5, Interesting)
Yes, and I can prove it.
I sail with a friend who's inner ears were damaged by an ear infection in childhood, leaving him with no inate sense of balance. So his entire balance is now done visually.
Does it slow him up? Well he's my dads age, is an ex British Olympic Fin Class sailor, and is now blue water cruising and is an Ocean Yachmaster / Instructor.
I guess if you can cope with the heaving deck of a yacht, you can cope with anything.
The advantage of course is that motion sickness is generally caused by a conflict of 'ear' balance and 'visual' balance (for want of better terms) so he doesn't get seasick. Thats the only way I actually found out, when I mentioned in conversation that he never got sick in rough seas, you'd never ever be able to tell otherwise.
Actually the reason you get motion sickness, and those panaromic cinemas fool you into thinking you are on a roller coaster is because your eyes are very important to navigation and balance.
Of course having the two systems (ear/visual) is a very good idea evolutionary, because one compensates for the weakness in the other.
But knowing that a blind colleuge of mine doesn't fall over in a heap, and my sailing companion doesn't either, I think I can justify in saying humans can operate with only one system perfectly well
Parent
no, but if you sling a few bars (Score:4, Interesting)
Wherever there is an intersection, replace the cross with a circle (diameter same or less than path-mark width), and program in a delay that allows the device to continue straight whenever it sees a circle, still looking for an unbroken path that will override the temporary step.
Another method is to mount the sensors front to rear, scanning for the path itself (inside edge)...not left to right, looking for the outside edge of the path as the legway does.
Parent
Re:Impressive but can you do this? (Score:3, Interesting)