Off-Roader new building instructions

I finally finished making great looking building instructions for the Off-Roader. You can download them here. I’m very happy with the results. The easiest way to do this is to get the LDraw suit. That comes with MLCad to build the robots, LDview to view the robots, and LPub for the instructions. What I did was I mainly built it in MLCad but i also used SR 3D building to help since some parts wouldn’t snap in right with MLCad, all you have to do is change the file extension from .ldr to l3b to use the MLCad file in SR 3D Builder. The last, and most important thing is that you need to add steps and rotation steps, just right click the box above the 4 building boxes in MLCad and click add step or add rotation step. . a rotation step rotates the robot in the directions since it will not dot hat automatically (note, in my instructions, every time the robot turned, I had manually put that in there. I also had to put every step in so when putting it into MLCad, build it in the order you would build it. Also, if you want to have the builder build a separate part first, build that , save it, then import it as a part in the final file. Then, open it up in LPub and look through the instructions and make sure they are correct, you can add more steps to a page by right clicking and clicking add step. I then used Adobe Acrobat to edit the PDF, add a cover page and make the parts list.

It is also possible to export an LDD as a MLCad file but you later have to put the steps in.

Final instructions here

If your confused and would like to see all the files, you can download them here (in Zip format)

Messing around with MLCad

So I do have about a week till I leave so I decided to mess round with building instructions since I didn’t like the ones I made for the Off-Roader. I did run into some problems though (I only did a little more than the first step)…..I can’t find the motor in MLCad and will have to download it and add it manually.

You can download it here.

UPDATE: I finally found and figured out how to install more NXT parts (I got them here) This is great because it also includes a part that i was missing and just ignored that is shown below (The Technic Beam  5 Bent 90 (3:3) with 4 Pins – the piece the holds the wheels)

Off-Roader building instructions

Off-Roader building instructions

Building instructions for the Off-Roader. Completely build able with NXT 2.0 set. Adding bigger wheels and PSP-NX-v3 is recommended if possible.

Download the PDF here

More info about the Off Roader in the last post

You can also use these gears if you don’t have enough of the black ones.

Download video: iPod/iPhone

Thanks to musikConomy for intro/outro music

Off Roader

Off Roader

This was my first attempt at an off-road vehicle and I think it came out pretty well. it is build-able with 1 NXT 2.0 kit (minus the wheels) and if you change the gears, you can build it with NXT 1.0.


I used only a NXT 2.0 kit along with 4 wheels I borrowed from a friend, this worked without borrowing wheels but these wheels make it work much better. I focused mainly on function not aesthetics since I’m not good at aesthetics anyways. in the back there at 2 motors next to each other and connected and then geared down about 1:2 (see Moment of Genius!!) with the wheels being so big, it was the same as 1:1 with the normal wheels in the end but it was still strong enough. my main problem with found while testing this was how it tips over easily because it doesn’t have a very low center of gravity ever since I added the big wheels. the other problem was that I don’t have a differential (and it’s hard to simulate one with  2 motors). when you turn to sharp, instead of turning sharp, it just goes straight (or slightly in that direction), especially on dirt. it was fine when I only turned slightly though.


I made 3 programs for this robot. 2 for people with a PSP-NX controller and one for people with just an NXT 2.0 kit  (or NXT 1.0 with and extra touch sensor)

Off Roader PSP-NX 2 joystick

Someone suggested to me that I should program it to be controlled by 2 joysticks instead of one (one for steering and 1 for speed) since it would be more controllable and thinking about it, many video games are similar to that (for example, I’ve seen people play uncharted and to walk to use the right joystick and to turn/look around you use the left joystick and in racing games the throttle is button and the steering is a joystick). I decided to try it and it works great. I still like the single joystick better but that’s because I’m used to that and I feel that I could get used to 2 joysticks easily. This program works by first having you set the center point of the steering with the D-pad and then speed is controlled by right joystick while steering is controlled by the left. Instructions are on the screen.

Download here

Off Roader PSP-NX joystick

This is the normal program that I would use for most uses the right joystick for all of the control. This is the control I used in the video. This program works by first having you set the center point of the steering with the D-pad and then speed is controlled by right joystick along with the steering. Instructions are on the screen.

Download here

Off Roader touch sensor

I made this program for people who only have an NXT 2.0 set. This uses 2 touch sensors as the remote which are both connected by the 50cm (20 inch) wires. Both buttons pushed makes the robot go straight forward, holding the left button makes it go left and holding the right button makes it go right. you can also select the speed on-screen (in increments of 20%). Instructions are on the screen.

Download here

All programs need the PID block from hitechnic

First 2 programs need PSP-NX block from mindsensors

Download: iPod/iPhone

Thanks to musikConomy for intro/outro music

New wheels

New wheels

Just borrowed these from a friend for the Off Roader

Some modifications are needed for the Off Roader because they work great but the gears keep skipping and then sliding off and the bar holding the gears and wheels in the back seems to just bend like Twizzlers sometimes when driving.

Moment of Genius!!

Moment of Genius!!

So I just realized how I can gear the robot down without running into problems disused in the last post. This was my (accidental) strike of genius!

So I was gearing the robot to go a bit faster (big to small to medium – black gears) so that the ratio would be 1.8:1

And I accidentally put the last gear (show above, bottom left) on the wrong side of the lift arm (shown below)

and I really meant to put that gear on the other side like I had been doing with the other gear setups.

Then I thought, hey, why didn’t I switch the gears around since there doesn’t have to be a gear on the other side (which was what was causing the problem because it was hitting the motor when it was too close – so this is what I ended up with:

So I then had 1:1.8 – i was trying to get 1:2 or 1:3 but this is good enough since it is easy and strong.

And then, of course, I messed around with the rotocasters

By the way – new wheels come on tuesday

Off Roader prototype

Off Roader prototype

This is my first prototype of thee Off Roader that I’m building. The gearing here is 1:1 but that will defiantly change since I’m going to get some bigger wheels from a friend (which obviously means more speed, less strength). Also, I plan on putting some sensors on it and then later, making the program work nicely and display things on the screen (currently it’s using the same one as on the motorcycle. Also I’m going to move the axle in the back that connects the two drive wheels together. I’m going to change the axle connected to the wheels and then connect the two sides together higher up so that  there is a higher clearance. Currently, it’s “Off Road” abilities are not very good since when it hits a bump, the wheel;s just slide instead of climbing up the wall. It defiantly has enough strength to move though. I had trouble with the gearing because I had to move the wheels down enough to get a good clearance but the problem was. If I made the first set of gears (currently black) smaller (using the medium-sized black gear instead of the big black one) the gear on the other side (small grey) hit the motor. if I switch the first gears around (so that the small one is on the motor not the big one) the big gear would cover the hole were the axle goes through right now. If I had made the last gear (the medium-sized grey one) bigger, the axle that the gear would go through would not be able to turn because it’s not a hole but an axle hole. – Any ideas?