LEGO WeDo Whiteboard Bot Rev 02

More advances on the whiteboard random art bot. I built a much stronger drawing arm, based on a design by LEGO master Yoshihito Isagawa.

It took some time to figure out exactly how I was going to connect the gears. I ended up using the chain: a student in LEGO Club built an impressive gravity powered car: it drops a weight that spins an axle connected by a chain to a a gear that is connected to another axle with wheels. The chains work very well.

I used the design in the bottom of the photo above. It is solid. Here's a look at it in action.


I swapped on a red pen as well. Rubber bands hooked around the pen and held by pegs make it fairly easy to swap pens.


I want to built cartridges like I did at CMK10 that are even easier to snap on and off the robot.

The problem with this revision is that the pen has a limited range of motion with this design. It does not make the beautiful mountains that the barely-in-control Rev 01 model exhibited.

My mind shifts to a trebuchet that a student built in LEGO Club.


Put a pen at the end of a pendulum. The motors randomly running back and forth will get the pendulum swinging: I could write an opening "routine" that was not random but rather got the pendulum swinging. Once it had a rhythm, the motor could run randomly back and forth to disrupt the rhythm. Onwards to Rev 03!