This Lego car is controlled by a Raspberry Pi with a BrickPi attached. It drives like a tank using joystick input from a USB logitech F310 gamepad. The wheels are directly connected to the Lego NXT motors. It also has ‘suspension’ because the plastic axles bend a bit. It can drive well on surfaces like gravel because the wheels need to slip as it turns since it drives like a tank.

The program uses threading to read input from the gamepad and drive the motors at the same time.

from inputs import get_gamepad
from BrickPi import *
import threading

BrickPiSetup()    #enable serial connection with BrickPi
BrickPi.MotorEnable[PORT_A] = 1   #enable motors
BrickPi.MotorEnable[PORT_B] = 1
BrickPi.MotorEnable[PORT_C] = 1
BrickPi.MotorEnable[PORT_D] = 1

quitting = False    #make variable quitting

def gamepad():    #a thread to read gamepad input
    while True:
        for event in get_gamepad():
            if event.code == "ABS_Y":   #run motors based on joysticks
                BrickPi.MotorSpeed[PORT_A] = event.state / -128
                BrickPi.MotorSpeed[PORT_B] = event.state / 128
            elif event.code == "ABS_RY":
                BrickPi.MotorSpeed[PORT_C] = event.state / 128
                BrickPi.MotorSpeed[PORT_D] = event.state / -128
            elif event.code == "BTN_MODE":    #quit
                global quitting
                quitting = True
                return

gamepad = threading.Thread(target = gamepad)
gamepad.start()

while True:
    BrickPiUpdateValues()   #update to run motors
    if quitting == True:
        sys.exit()    #full quit

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