Overview
The final project of Engineering Physics Laboratory II (semester 4): build a wirelessly controlled car that plays soccer by pushing the ball into the opponent’s goal.
System
- Controller: ESP32, receiving commands over WiFi from a phone app.
- Drive: DC motors driven by an L298N motor driver.
- Steering: a servo turns the front wheels.
- Kick: a DC motor with a rod attached spins until the rod hits the ball and sends it flying.
- Dribble: two servo-driven “doors” at the front of the robot open and close like arms to hold the ball and release it.
- Power distribution board (PDB): a custom board that turns the 12 V battery into both 12 V and 5 V outputs, with indicator LEDs.
- Chassis: designed in SolidWorks (see the CAD model above).
Power Distribution Board
The motors run on 12 V, while the ESP32 and servo need 5 V, so the board splits one battery into two rails. The 12 V input enters through a screw terminal, a linear regulator steps it down to 5 V, and both rails leave on pin headers. Capacitors on the regulator’s input and output smooth the supply, and an LED on each rail shows that it is live.
Controller App
A phone app connects to the robot by IP address. It has drive and rotate buttons, kick and dribble buttons, and speed levels from 1 to 5.
My Contribution
I handled the mechanical, electrical, and software work:
- CAD: designed the chassis, including the kick and dribble mechanisms, in SolidWorks.
- PCB: designed the power distribution board, which the team fabricated in the Engineering Physics workshop.
- Firmware: programmed the ESP32 with Arduino.
- Controller app: built the phone app used to drive the robot.
Result
The team won Best Design in the FTI Cup for Engineering Physics Laboratory II (2024).
Limitations
- Weak grip on the ball: the dribble arms do not hold the ball firmly, so it still slips out when the robot brakes suddenly while carrying it.