The BuddyBot concept sketch had a movable arm to keep your personal items, an LED display attached to the head, 2 IR sensors that can be waved at, a pet area at the top of the head, and various buttons at the base. Although not shown in the sketches below, we added a chocolate dispenser to the idea, that will be attached to the other side of the body.
The design of BuddyBot was done keeping in mind the given design constraint (dimensions should not exceed 50 cm x 50 cm x 100 cm), and a personal constraint to fit all wirings, breadboards, and power supply inside the body.
The body consists of 3/16 inch sheets with teeth so that they can be joined into a 3-dimensional shape. Holes are cut into the sheets to accommodate various buttons, servo motors, sensors and joystick.
The head is elliptical-shaped, with a rectangular cut to fit the LED displays, and a cut underneath so that it could rest on the neck.
The hand was designed to fit at the end of the arm - there is a cavity in the hand so that the distal end of the arm can go inside by an inch. The arm itself is double the thickness to prevent buckling.
The overall height of the BuddyBot is 17.2 inches (44 cm), and the base is 10.5 inches by 12 inches (27 cm by 30 cm).
BuddyBot's dispenser provides a Lindt chocolate to the user whenever they finish the game. The dispenser uses a rack-and-pinion system powered by a servo. The gear rack system is able to achieve around 1.4" of linear actuation, which is enough to drop the chocolate ball, and then push it forwards. There is a storage cylinder with a lid that can store around 4 chocolate balls.
The dispenser system, the hand, and the head were all 3D printed using PLA filament. The rest of the body, consisting of just sheets, were laser cut from 3/16" duron available in the PRL.
The laser cut duron was painted to white using spray paint, and multiple coatings were applied to achieve a rich, white color. The sheets were then assembled, and hot glue was applied internally, along the edges. The hand was also attached to the arm using hot glue. Given the load conditions of a coat and a couple of keys, the arm system was able to handle it well. The dispenser and servo motors were each attached with 2 sets of M3 bolts with low profile M3 nuts, and the joystick was attached with two screws.