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.

Building Instructions

You can download the building instructions here(PDF)

You can download the LDraw files here(Zip)







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

Thanks to musikConomy for intro/outro music

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