Simple yet powerful extension to Flexy2. It is a complex dynamical system, that contains one actuator, the fan. This fan then drives air into the tube, where a plastic floater is then lifted from the bottom position. An infrared proximity sensor then measures the position, which constitutes a measured and controlled process variable. It comes with two knobs, that are fully configurable. As the Flexy2, it comes with a Matlab/Simulink interface using which students can easily implement and test their own control strategies. This device can also serve as a perfect demonstrator device, using which the teacher can simply demonstrate the difference between a bang-bang control compared to the smooth performance with a PI controller.


  • contains embedded microcontroller (Arduino UNO)
  • 4-digit segmented display
  • two configurable user inputs (knobs)
  • durable 3D printed case
  • compatible with all computer platforms (Windows, Linux, Mac)
  • MATLAB/Simulink and Python interface
  • programmable directly in C language
Power supply12 VDC
Dimensions of the case (w×h×l)15.1 cm × 7.8cm × 4.8 cm
Dimensions with the tube (w×h×l)15.1 cm × 48.0cm × 4.8 cm
Fan specs40 mm, 12 VDC, 4 W
ConnectionsPC/Mac via USB or 6-pin IDC with PLC-like controllers
Proximity sensor12bit resolution
Sampling rateup to 200 Hz with Matlab or Python