Top Level Design:

 

Side View Of System:

Circuit Diagram:

Parts:

(3) Renogy E.FLEX5 Portable Solar Panel with USB Port for $29.99 each

(3) Justin 10400mAh Portable Power Bank with LCD Display for $24.99 each

(8) Set of 100 Lego Chain Links for $15.99 each

(4) Phototransistor for $0.95 each

(1) Micro Gearmotor – 90 RPM (6-12V) + enclosure for $14.45

(1) 5X2 OSB Sheet for $16.75

(1) Arduino Uno RedBoard (previously owned)

(1) H-Bridge Motor Driver SN754410 (previously owned)

(4) 23 K Ohm Resistors (previously owned)

(X) Assorted Lego Pieces (previously owned)

Total Cost (Includes Shipping and Handling Fees): $341.75