Lego robots

First, here is the simplest wall follower robot one can build: it uses a Scout in "normal" mode, so no programming is required! Just set the two touch inputs to "brake" and wire every thing in the right order... The trick is the rubber band: when the robot is away from a wall, the rubber band pulls the arm against one of the contact, so the robot turns toward the wall. When the robot is at the right distance from the wall, no switch is pressed, so the robot moves in a strait line. If the robot gets too close to the wall, the opposite motor stops and the robot turns away from the wall.

Using two touch sensors and a side arm are enough for right hand turns, but how does the robot makes a left hand turn? Well, the trick is to get that curved piece just right, so when the robot hits a wall in front of itself, the arm gets pushed like when the robot is too close to a wall on its right side. That's it! I have to admit that I copied the idea from a very simple kit that you can buy from the robot store: it is a mouse shapped robot that has two motors, two AA batteries and a single pole double throw mometary switch attached to a curved arm... No fancy electronics required! I think that his could be duplicated in Lego using just Technic components: no need for Mindstorms! But I have to say that the various sounds settings on the Scout adds a lot to the fun!

These robots are meant to be controlled directly from the computer, in quasi real time. The first version, pictured below, has some simple tasks in memory, things like: move left thread forward for 0.1 second. The computer then starts the various threads in accordance with the user input. Right now the "user input" consists of clicking buttons... I've just got a sample programm to read joystick data from Visual Basic, so I'm trying to use a gamepad to control the robot.

Click on the various parts of the robot to see different views.

In order to control the robot(s) over a greater area, I needed something to hold the IR tower about 3' off the floor... So I built it in Legos. I also finally found a use for this old (and heavy) laptop! It's just one step up from being a door stop...

One of the more original robot I've built so far is the Marbl'bot: it uses four balls from Logitech's TackMan Marble Fx track balls (the fact that I work for Logitech made it easy for me to get them). Using two motors, it can travel in any direction, without ever turning its body! I guess this is similar to a synchronous drive... Since these pictures were taken, I've built a new, simpler, version that uses four motors, so by inverting the connexions on two of the motors, the robot can rotate itself.