🤖 The Bumper Car Robot Build

Mechanical & Power Foundation: I completed the physical assembly of the 2-wheel differential drive setup, integrated a ball caster for stability, installed 2 motors, and wired up the battery.

Control & Wireless System: I added a wireless transceiver and an external programmer to flash code onto the robot.

Smart Hardware Choice: To save time, I skipped designing a custom PCB from scratch and chose the Baby Orangutan B-328 Robot Controller, which perfectly combines an ATmega328P microcontroller and a dual H-bridge motor driver in one compact package.

🎮 Custom Controller CAD Design (Autodesk Inventor)

Shell Geometry: I created the main gamepad faceplate and used the Shell tool to seamlessly hollow it out, establishing a uniform, clean 3D enclosure.

Joystick Integration: I spaced the thumbstick centers 3 inches apart and sized the clearance holes to 21mm to ensure full range of motion. On the inside ceiling, I successfully sketched and extruded 5mm outer / 2.5mm inner mounting bosses tailored for secure M3 screws.

Battery Cradle Optimization: After realizing a 4 AA holder was too large, I pivoted to a compact 2 AA holder (1.25 in x 2.5 in). I successfully mapped out its boundaries in the center channel and extruded a 0.30-inch-high 3D nesting cradle with 0.08-inch walls to lock it in place.

Power Switch Cutout: I oriented the workspace to view the flat back wall from the outside and used the Extrude (Cut) tool to pop a perfect rectangular slot straight through the shell for the main power switch.

Brain Placement: I moved back to the inside floor of the controller to map out the micro-mounting standoffs (0.08 in inner / 0.16 in outer circles) to keep the microcontroller safely elevated.