This chimney climber should be considered as the first ‘robotic’ climber in the series. Contrary to the older two climbers, this robot uses sensors to tell the robot about its environment. A Mindsensors.com acceleration sensor measures the robot’s tilt on one axis. When unbalanced, the wheel speeds can be adjusted to regain balance. An Ultrasonic...

I received the 8273 Technic set, the “off-road truck” late 2008. Having finished building it, I thought it would be fun to add an NXT and two motors to NXT-ify it. The NXT turned out to fit nicely in the back of the truck. The steer and rear driving wheels are motorized, but you must...

The aim of this sorter was to demonstrate the functionality of a homebrew color sensor, based on the instructions in the “Extreme NXT” book. I have the first edition of the (excellent) book, but the second improved version also has instructions for this color sensor. Below you’ll see the resulting sensor. Three colored LEDs are...

This little jumping robot jumps around on one foot with the help of a walking frame. Youtube viewers collectively suggested it reminded them of an old lady (I can’t blame them). To get a good idea of how it works, just have a look at the video, which is quite self-explanatory. If you have the...

Brick sorters are one of my favorite Mindstorms projects. Simply because they’re fun, and also because they’re more “useful” than most LEGO vehicles that just drive around. This design was made in early 2007, and I shared the building instructions later that year. This was the first time I shared building instructions with the community,...

This is the first biped walker that I built with the NXT. It’s bigger than Alpha Rex, and it walks a bit less elegant. Yet, it actually lifts its feet off the ground to walk. It walks by lifting up one foot, while turning the foot that is currently on the ground. When it does...

This little dog was developed in November 2007. It walks around while wagging its tail and while looking for humans or objects in its way. You can build it if you have the NXT 1.0 set and three extra gears (details below). Building instructions and the program are available for download. This is a picture...

This is the fourth evolution of brick sorters! This time sorting 10 types of bricks: 5 colors and two sizes. You can simply throw a set of bricks into the sorter, and the machine will handle the rest. Compared to sorter #2, this one is more reliable and more functional too. This robot uses both...

This robotic arm combines the power of the RCX and the NXT. The robot turns on its stationary base while grabbing objects around it. The RCX and NXT talk to each other by sending light pulses with light sensors. The RCX acts as the on board master, and it receives infrared control messages from a...

This line follower uses three light sensors. One of them is an NXT light sensor, while the other two are RCX light sensors, attached to the NXT with custom converter cables. To make a converter cable, cut one NXT cable and one 9V style cable. Next, connect the black and white wire from the NXT...