Snek Drives a Lego Car

(click on the picture to see the movie)

This is made from:

You can get everything other than the light sensors from various vendors.

More Pictures

Here's a picture from the front showing the light and light sensor mounted next to each other.

And here's the car from the rear showing the motor connections, the other light sensor/light combination and the battery pack:

Source Code

This program is a bit more verbose:

    mr = (MOTOR1A, MOTOR1B)
    ml = (MOTOR2A, MOTOR2B)

    pf = SIGNAL1
    pr = SIGNAL2

    f_speed = 0.5
    r_speed = 0.5
    t_speed_f = 0.6
    t_speed_s = 0.2

    def forw():
        talkto(mr)
        setpower(f_speed)
        setright()
        on()
        talkto(ml)
        setpower(f_speed)
        setleft()
        on()

    def back():
        talkto(mr)
        setpower(r_speed)
        setleft()
        on()
        talkto(ml)
        setpower(r_speed)
        setright()
        on()

    def left():
        talkto(mr)
        setpower(t_speed_f)
        setright()
        on()
        talkto(ml)
        setpower(t_speed_f)
        setright()
        on()

    def right():
        talkto(mr)
        setpower(t_speed_f)
        setleft()
        on()
        talkto(ml)
        setpower(t_speed_f)
        setleft()
        on()

    def stop():
        talkto(ml)
        setpower(0)
        off()
        talkto(mr)
        setpower(0)
        off()

    def go_forw():
        forw()
        listento(pf)
        while read() < .25:
            pass
        stop()

    def go_back():
        back()
        listento(pr)
        while read() < .25:
            pass
        stop()

    def bumper():
        while True:
            go_forw()
            back()
            time.sleep(0.5)
            stop()
            left()
            time.sleep(0.25)
            stop()
            go_forw()
            go_back()
            go_forw()

    bumper()