anchor.diff:  
       use sensor  = model.ObjectSensor
       use buttons = model.Buttons
  -    use xServo  = model.Servos.[C1]
  -    use yServo  = model.Servos.[C2]
   
       let sensorOutput = sensor.ToObservable()
       
  
positive.code:                           |> Observable.filter (fun x -> ButtonEventCode.Up = x.Button)
                            |> Observable.subscribe (fun _ -> exit.Set() |> ignore)
  
  //    use timerSetterDisposable = Observable (System.TimeSpan.FromSeconds 40.0) 
  //                                |> Observable.subscribe (fun _ -> sensor.Detect())
      
      buttons.Start()
      sensor.Start()
      Shell.send """v4l2-ctl -d "/dev/video2" --set-ctrl white_balance_temperature_auto=1"""
  
      model.LedStripe.SetPower (75, 20, 20)
  
  
negative.code: 
      use ledstripeDisposable = colorStream.Subscribe model.LedStripe
  
      let locationStream = sensor.ToObservable()  
                           |> Observable.choose (fun o -> o.TryGetLocation)
                           |> Observable.filter (fun loc -> loc.Mass > minMass)
  
      use xPowerSetter = locationStream 
                         |> Observable.map (fun loc -> -loc.X)
                         |> Observable.scan (fun acc loc -> scale maxAcc acc + updatePositionX loc) 0
                         |> Observable.subscribe model.Servos.[C1].SetPower
  
      use yPowerSetter = locationStream
                         |> Observable.map (fun loc -> loc.Y)
                         |> Observable.scan (fun acc loc -> scale maxAcc acc + updatePositionY loc) 0
                         |> Observable.subscribe model.Servos.[C2].SetPower
      
      let observableButtons = buttons.ToObservable()
      use downButtonDispose = observableButtons
  