Added web robot example

examples/web_robot.rb

@@ -0,0 +1,102 @@
+require 'rubygems'
+require 'ev3'
+require 'ev3/connections/bluetooth'
+require 'webrick'
+require 'json'
+
+
+class Robot
+  RIGHT_MOTOR = 'b'
+  LEFT_MOTOR = 'a'
+  CLAW_MOTOR = 'c'
+
+  MAX_TURN = 40
+
+  def initialize
+    @brick = EV3::Brick.new(EV3::Connections::Bluetooth.new('/dev/rfcomm0'))
+    @brick.connect
+    @brick.beep
+
+    motors.each do |motor|
+      motor.stop
+      motor.speed = 0
+      motor.start
+    end
+  end
+
+  def claw_speed
+    claw_motor.speed
+  end
+
+  def claw_speed=(speed)
+    claw_motor.speed = speed
+  end
+
+  def move(speed, turn)
+    turn_size = (MAX_TURN * turn).round
+    drive_speed = (speed >= 0 ? [speed, 100 - turn_size.abs].min : [speed, -100 + turn_size.abs].max).round
+    left_motor_speed = drive_speed + turn_size
+    right_motor_speed = drive_speed - turn_size
+    puts [left_motor_speed, right_motor_speed].inspect
+    left_motor.speed = left_motor_speed
+    right_motor.speed = right_motor_speed
+  end
+
+  def reverse
+    left_motor.reverse
+    right_motor.reverse
+  end
+
+  def stop
+    motors.each do |motor|
+      motor.speed = 0
+      motor.stop
+    end
+  end
+
+  def disconnect
+    brick.disconnect
+  end
+
+  private
+
+  attr_reader :brick
+
+  def motors
+    [left_motor, right_motor, claw_motor]
+  end
+
+  def left_motor
+    brick.motor(LEFT_MOTOR)
+  end
+
+  def right_motor
+    brick.motor(RIGHT_MOTOR)
+  end
+
+  def claw_motor
+    brick.motor(CLAW_MOTOR)
+  end
+end
+
+robot =  Robot.new()
+
+server = WEBrick::HTTPServer.new(:Port=>2000)
+
+server.mount_proc '/' do |req, res|
+  puts "Received #{req.body}"
+  parsed = JSON.parse(req.body)
+  angle = parsed['angle']
+  throttle = parsed['throttle']
+  throttle = (throttle * 100).round
+  angle = angle.abs < 0.25 ? 0 : angle
+  puts "Setting Angle: #{angle}, Throttle: #{throttle}"
+  robot.move(throttle, angle)
+end
+
+trap("INT") do
+  robot.stop
+  robot.disconnect
+  server.shutdown
+end
+server.start