StringThing
June 17th, 2008 by NXTMongerThe StringThing uses one motor to spin a string. That’s it. Oh right: it spins it in a sine wave. Cool, huh?
The StringThing uses one motor to spin a string. That’s it. Oh right: it spins it in a sine wave. Cool, huh?
Here is a really cool Bobcat that i found on you tube, it uses Lego pneumatics to control the lift and tip of the bucket. This is a really good example of how one can combine pneumatics and the NXT together. I wish there were more information on it so that it would be easier to replicate, or make improvements.
Well even though this is not an NXT Creation I think it is still awesome. As most of you know NXTLiftBoy has made several really cool creations. You can check them out over at MOCpages Here.
Here is what he has to say about it:
The ChainRider is a trike featuring two huge wheels, remote control, and, i dare say, excellent drive properties. It is made entirely from a single LEGO set 8275, but appears to be much more fun in playing than the bulldozer!
For more information and building instructions see: http://www.mocpages.com/moc.php/54200
I challenge anyone to try to make a similar version of this with an NXT at the control.
Here is a pretty cool project that Sascha from Germany Sent me.
Here is the information from Sascha:
“This is the Lego NXT “4 In A Row” robot project.
This robot is able to play against you on itself.
He is independend of any computer, so the program - programmed with NXC - is running on the NXT brick.
The human player can choose the row while pushing the touch sensor as often as the row’s number. The computer decides on its own, which row would be the best for it.
This KI is working mainly on the MINIMAX algorithm. However the computer is not as hard as i want him to be, because of the less NXT Brick speed.
the algorithm works like that: The computer simulates the next 3 possible steps and gives any game situation a specific number of points. The Row with the most points will be the next computers choice.
The robot uses three NXT motors:
- one is moving the gameboard
- the second fixes the stones
- the third opens the gate”
Check this out!! This is a really good example of a robot playing instruments. From what I see it records what he drums and plays the beat back. How cool!!!
Here is a really good example of what you could do with one NXT Retail Set and no other parts or sensors needed. A Rubik’s Cube solver!!! It uses just the retail kit. It seems like a simple design but would be a complex program. The following is some specks on it:
Here is his website and a video of it in action.
http://tiltedtwister.com/index.html
(Edit) The Maker has added the LDD File and Program files on his site, so head on over there and build one for yourself.
I have finally got around to making the video for Dozer. It has been a while since I built this and I forgot how powerful it actually is. As you can see in the video it can shove around the large pile of bricks around with ease. It has a Little Bit of trouble driving over it because the plow is so heavy it tips forward a bit. Having the plow so heavy is a good thing because it helps scrape the ground and move alot of stuff around. There is also a couple of surprises in the video, I decided to try out how well the little Power Functions Tank I built, worked on all the legos. It did surprisingly well. I did not think the the new tracks would preform that well on legos but they worked great. The other little surprise is my dog made her first appearance in my videos.
After Building a light box to take better photos out of PVC Pipe, I had a Bit of excess pipe laying around so I got to thinking, What if I could build something that could move along over a pipe with ease.
So that is when I got to thinking, I needed 8 wheels, 4 on each side so that it has enough traction to move along the pipe under a heavy load. After I had built the prototype I figured out that it was going to be difficult to power all of the wheels with just one motor.
At first I tried chains but found out that wouldn’t be strong enough, and would be very easy to do in the first place. This is mostly because the wheels on each half turn different directions.

To be able to get them to turn like this I was lucky enough that the distance was perfect so I could use the right amount of gears. To turn the wheels different directions as shown above. From what I had to work with I came up with this design:

When I was done getting the Moving part of things done, I worked on the lifting mechanism. After several attempts to get the perfect ratio on the gears from the motor to the drum where the string is wound onto I moved onto the pulley system.

After Building and testing Pipe Runner on the small Test piece of pipe I had and deciding that it would work good enough, I decided that I would then go ahead and build the pipe structure to be able to run on. I started simple, but then realized that I needed somthing more stable so i added more pipe to sections to make it stronger.
Due to the strength of the PVC pipe Pipe Runner is only able to lift about 5 Pounds. That is my only disappointment with it. If I ever decide to make another one similar I will either use metal pipe or enforce the current one. Other than the pipe not holding very much I believe that Pipe Runner Works very well and I like how it turned out.
I used the Mindsensors.com Sony Playstation 2 Controller interface to control it in the video. Programming anything to be extreamly accurate with string is very hard due to the string winding up on the spool different ways every time. Using the PS2 Sensor makes hooking very simple and easy.
Please feel free to post any questions, comments, improvements or if you need help with the Pipe Crawler at the Forum. Click Below:
TopThis is the Top of Pipe Runner. You will need to attach the bottom part to it as shown in the pictures below. |
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BottomThis is the Bottom of Pipe Runner. You will need to attach it to the top as shown in the pictures below. |
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SideThis is the Side of Pipe Runner. You will need to build 2 of these and attach them to the top part on each side as shown in the pictures below. |
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ProgramThis is the Program for Pipe Runner. It uses various Buttons and the analog stick to move and operate the functions. |










Here is a pair of Claws that I discovered on YouTube that I found very cool. These look like they work very well and are somewhat simple. I may try something like this for fun when I have one of mine taken apart.
2+1 = 4 . This robot’s function is a special drive train called a Motor Multiplexer. It works by having 2 motors to drive the vehicle, and another motor in between the 2 to slide them forward along a gear rack. When they are in the front position a bump sensor is pressed, and it stops the center motor. The 2 motors are now disengaged from the wheels, and engaged to the 2 worm gear-boxes on the front, which have attachments on them. So, basically, it’s purpose is to have 2 powered drive wheels and 2 powered attachments, with only 3 motors. It was originally designed for FLL.
Video Found Here: LEGO MINDSTORMS Motor Multiplexor