Pets I Own: Low-life for Highbrows

Using LEGO Mindstorms® Kits


Built by NJG: 5/3/2000

My first bot was based on the one described in the LEGO Mindstorms Scout manual (without the wings and bug-eyes). I had to start somewhere :-) The major modification was the introduction of 'railings' along the side of the processor unit to keep the motor and sensor cables clear of the tractor wheels or other external objects. The "dot" in front of the rover is a 25 cent coin (approx. 1 inch in diameter) to give some idea of scale.

Motorized Free Gyroscope

Built by NJG: 5/11/2000

Not exactly a robot, but it proved to be an interesting mechanical challenge using the available LEGO components.

 Prototyped with LEGO Mindstorms Scout®
 Improved with LEGO Mindstorms RCX®

Three sybsystems provide the 3-degrees of rotational freedom:

  1. Motorized flywheel
  2. Vertical gimbal
  3. Swivel base

Manual mode (shown)

Allows you to feel the forces!
Twist base to the left or right

Auto mode (Using the RCX; not shown)

Uses sensor to automatically swivel the base

How many RPMs is the flywheel doing?

I had no idea, so did an experiment to determine it. I used a Lego motor direct-driven Tractor wheel (like that shown in the photos above) and a 26 inch bicycle wheel. With the electric motor on and the tractor wheel rotating, I applied its rubber surface to the rubber of the bike wheel. When the bike wheel got up to constant speed under friction, I used the audible beeping of the Scout brick to count the number of beeps it took for the bike wheel to do one rotation. A single rotation was defined by noting the (arbitrary) position of the air-valve on the bike wheel, and counting beeps until the valve returned to that same position.

Here are the results: