When you run Minerva's program, she drives straight forward. When the light sensor (mounted on the end of the grabber arm) sees something dark, Minerva stops driving. She uses the arm to try

to pick up whatever the light sensor saw. Then

she turns around and drives back to her starting point. She puts down whatever she's carrying, turns around and is ready to start again.

Building Instructions

If there's one lesson to be learned from Minerva, it is that mechanical design is hard. I had to build this robot five times to get it right. And I don't mean I moved a few pieces around—I actually

disassembled and rebuilt the robot that many times. The drivetrain alone took four tries before I got it right.∗

Directional Transmission and Drivetrain

The long gray piece in Step 1 swivels freely on the shaft.

∗ Minerva uses almost all of the gears that come with RIS 1.0. Unfortunately, RIS 1.5 comes with fewer gears (five 12t gears instead of eight). To get the extra gears you'll need for Minerva, you can

order the #5229 Gears & Differentials parts pack from the LEGO Shop At Home Service, (800) 453–4652. Cost is $4.50 including shipping.

The 8u shaft in Step 2 is loose and may fall out. It will be anchored in the next step. The 6u beam, like the long gray piece from Step 1, swivels freely on its shaft.

Figure 5-1.

Minerva, a mechanical masterpiece

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