Part 2 of a beginner Arduino robotics series covering the physical build of 'Clusterbot', a $50 autonomous robot. Topics include selecting a round acrylic chassis for differential drive, assembling a Tamiya twin-motor gearbox (58:1 vs 204:1 gear ratio tradeoffs), choosing Mabuchi 3V toy motors vs 6V alternatives for the TB6612FNG driver, wheel and ball-caster installation, balance considerations for a two-wheel plus caster design, and a dual-battery power arrangement using 2xAA for motors (VMOT) and a separate 9V for the Arduino.
