Insect: An Eight Legged Robot

By Sivan Toledo
July 2007

These are building instructions for an 8-legged robot. The focus here is on a platform for legged locomotion. As you can see in the picture below, my robot carries two custom sensors, so you can't build an exact replica of it, but you can build the robot without the sensors and add your own. My sensors are an acceleration sensor that is used here as a tilt sensor, and a pitch sensor. The robot waits for a sound of 2048Hz, and then it starts walking. It keeps on walking until it senses that it has been flipped upside down. Then it plays dead and stops walking. It starts walking again if it hears another 2048Hz sound.

I have built legged walkers before, but they didn't carry their battery box (or the NXT). Here I wanted the robot to carry the NXT brick, which is pretty heavy due to the six batteries. To make the robot stable, I mounted the NXT on the bottom, facing down, so you can easily operate its buttons. Mounting the NXT on the bottom keeps the center of gravity of the robot low. This is one interesting aspect of the robot.

Another interesting aspect of the robot is the fact that it looks symmetric, but it is not exactly so. Its two sides are close to being mirror images of each other, with one motor facing forward and the other facing backwards. This distributes the weight evenly, which agains helps keep the robot stable.

Here is the finished robot.

Now let's start to build.

Now the platform is ready. we need to add sensors on top and the NXT on the bottom. The next few pictures show how I mounted my own custom sensors, but for most of you, this is pretty irrelevant.

Now we are going to mount the NXT. The yellow connectors allow you to quickly release the NXT from the robot (to change batteries, for example).

That's it, we're done!

© 2007, Sivan Toledo