NXT Monster Truck - Part 1

Have you ever picked up your NXT kit and decided to build just a robot with no sensors, no autonomy and pure fun?

That is what I did over the weekend. Inspired by a Monster Truck in the latest 'V' energy drink advert, I decided to build a remote controlled monster truck robot.
The picture on the left is the real remote controlled monster truck from the advert, and the one on the right is the NXT version !

The only thing the NXT is doing in the truck is to provide power to the motors and act as a Bluetooth receiver for my my mobile phone I was using to control the robot!


To get the real feel of a Monster truck, I used 4 TECHNIC tractor wheels, and 4 PF-XL motors. You can use the adopters available from the LEGO Shop @ Home to connect the 4 PF motors to the 2 motor ports. The second picture shows how the two left hand motors are connected to the same port in the NXT.

With 4 direct drive wheels, the vehicle can handle any terrain. The giant tractor wheels are amazing - it is great to watch it climb over rocks, mud and ride through long grass - that normal NXT robots struggle with.

Check out the video ...


In the coming weeks, I will be extending this vehicle with more autonomy, more features .....

Deals on NXT Sets?

Right now, LEGO sets are on Sale at Toys R Us---at least online. (I don't know how long the sale lasts.)

The Good News — Their offer is "Buy 1, get 1 half price".

The Bad News - The full price is $290!!!

In the end, if you want two sets, or can share they deal with someone else, you end up paying $217 for each of the two sets---which is an unusually-good discount.

Anyone know of other special deals right now?

FLL Mission Overview Part 8 - Fund Research or Corrective Action

Objective: Move the money (yellow ball) to the research area (the top left corner) or the research area (bottom right corner) so it's not touching any of the mat outside it.

Point Worth: 15

Mission Location: Ball starts near the house, somewhat in the top right corner. It needs to be move to the research area (top left corner) or the research area (bottom right corner).

Estimated Difficulty Level: Medium

Time Length Rating: 4/10

Unique Challenge Aspects: Watch out for the house! Also - is it just me, or does the yellow ball roll more freely than the gray ones?

Richard

NXT Peg Sorter

This NXT Peg Sorter will sort long black NXT pegs from long gray pegs, into two separate bins. A conveyor feeds pegs down in a chute, then the light sensor is used to see the color of the peg as it is sliding down the chute, then a hitting arm hits the black pegs to the side while allowing gray pegs to fall straight down into the other side.

Here is a video of the machine in action:

There are simpler and more reliable ways to sort pegs, but with this project I wanted to do something similar to the way some modern high speed mechanical sorters work in factories. In some of these machines, the items are thrown quickly past a gap in the conveyor belt, where an optical sensor looks for rejects, and then air jets are used to knock the rejected items down through the gap into a reject bin, while the good items continue past the gap to the other side. The challenges are to quickly detect a reject and then to get the right timing between seeing the reject and pushing it out of the fast moving stream. An example is this machine for sorting vegetables (see also the video at the end of the page). Another example that is simpler and closer to how this peg sorter works is seen in this video of a colored pencil sorter.

In this NXT Peg Sorter, the gray pegs are the "good" pegs, and the black ones are the "bad" (e.g. burnt) ones that need to be rejected. The speed of this sorter is limited by how fast the hitting arm can recover after hitting one black peg (not nearly as fast as an air pressure jet can recover), but the rest of the machine is capable of sorting much faster. I didn't put that much time into designing a good hitting arm, so there is definitely room for improvement here. How fast can it get?

Gaze following robot

Here is another example of how the NXT can be so much more than just a toy. A group of researchers from Technical University of Denmark and the IT University of Copenhagen have built a robot that goes in the direction that you look.

Here's how it works; You sit in front of a computer that has sophisticated eye tracking software (that's right, it knows where you're looking!) It then sends commands via wifi to a robot that has it's own laptop. This laptop then calculates how much power needs to go the motors, and sends appropriate commands to the 2 NXT's onboard. These then drive the motors appropriately. A webcam connected to the laptop streams back video of where the robot is travelling.



I'm thinking it might be possible to bypass the onboard laptop completely, and have the main PC send commands directly to the NXT. You could then put on a cheap wireless video camera to give you the robot's point of view.

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Damien Kee

NXT Plotter

This fantastic plotter uses the Eclipse development environment to process an image. It then send the information to the NXT via bluetooth, which is running lejos.

I quite like how it drives backward for each newline, as opposed to having a fixed workspace. In theory it could do whole banners (although I'm sure it would be quite slow :D )



More pics at http://www.xframe.com.br/printer/

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Damien Kee

Happy Thanksgiving

For those celebrating today, Happy Thanksgiving!