Prabakar and Sonar and @zmatt...

# w/ help from #beagle on Freenode
# and w/ help from Prabakar on his book "BeagleBone by Example."

from flask import Flask, render_template
import Adafruit_BBIO.GPIO as GPIO
import Adafruit_BBIO.PWM as PWM
import time
from rangeI import Range
import serial

sonar = Range("/dev/ttyS2")

class Motor:
    def __init__(self, dir_pin, pwm_pin, pwm_freq):
        self.dir_pin = dir_pin
        self.pwm_pin = pwm_pin
        self.value = 0

        PWM.start(pwm_pin, 0, pwm_freq)
        GPIO.setup(dir_pin, GPIO.OUT)

    def set(self, value):
        assert -100 <= value <= 100
        if (value < 0) != (self.value < 0):

            # changing direction
            PWM.set_duty_cycle(self.pwm_pin, 0)
            GPIO.output(self.dir_pin, value < 0)

        PWM.set_duty_cycle(self.pwm_pin, abs(value))
        self.value = value

motor1 = Motor(dir_pin="P8_18", pwm_pin="P9_16", pwm_freq=2000)
motor2 = Motor(dir_pin="P8_16", pwm_pin="P9_14", pwm_freq=2000)
motor3 = Motor(dir_pin="P8_14", pwm_pin="P8_13", pwm_freq=2000)
motor4 = Motor(dir_pin="P8_26", pwm_pin="P8_19", pwm_freq=2000)

app = Flask(__name__)
@app.route("/")
# @app.route("/<state>")
@app.route("/<take>")

def Distance(take=None):

    distance = sonar.measure()
    print("distance =", distance, "inch")
    time.sleep(2)

    if take == distance >= 8:
        motor1.set(0)
        motor2.set(0)
        motor3.set(0)
        motor4.set(0)
        print("Stopping Motors!")
        time.sleep(0.2)

    template_data = {
        "title" : take,
    }
    return render_template("Boot.html", **template_data)

@app.route("/<state>")

def updates(state=None):

    if state == "F":
        motor1.set(100)
        motor2.set(100)
        motor3.set(100)
        motor4.set(100)
        time.sleep(0.2)

    if state == "L":
        motor1.set(15)
        motor2.set(85)
        motor3.set(15)
        motor4.set(85)
        time.sleep(0.2)

    if state == "R":
        motor1.set(85)
        motor2.set(15)
        motor3.set(85)
        motor4.set(15)
        time.sleep(0.2)

    if state == "S":
        motor1.set(0)
        motor2.set(0)
        motor3.set(0)
        motor4.set(0)
        time.sleep(0.2)

    if state == "REV":
        motor1.set(-75)
        motor2.set(-75)
        motor3.set(-75)
        motor4.set(-75)
        time.sleep(0.2)

    if state == "REV_L":
        motor1.set(-75)
        motor2.set(-25)
        motor3.set(-75)
        motor4.set(-25)
        time.sleep(0.2)

    if state == "REV_R":
        motor1.set(-25)
        motor2.set(-75)
        motor3.set(-25)
        motor4.set(-75)
        time.sleep(0.2)

    if state == "SPIN_LEFT":
        motor1.set(100)
        motor2.set(-100)
        motor3.set(100)
        motor4.set(-100)
        time.sleep(0.2)

    if state == "SPIN_RIGHT":
        motor1.set(-100)
        motor2.set(100)
        motor3.set(-100)
        motor4.set(100)
        time.sleep(0.2)

    template_data = {
        "title" : state,
    }
    return render_template("Boot.html", **template_data)

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=False)