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@PHDTHESIS{Beckmann:793926,
      author       = {Beckmann, Felix},
      othercontributors = {Schomburg, Werner Karl and Schmitz, Katharina},
      title        = {{M}ikropfeifen als {S}ignalgeber im {U}ltraschallbereich},
      school       = {Rheinisch-Westfälische Technische Hochschule Aachen},
      type         = {Dissertation},
      address      = {Aachen},
      reportid     = {RWTH-2020-07274},
      pages        = {1 Online-Ressource (x, 104 Seiten, Seite CV-CXXI) :
                      Illustrationen, Diagramme},
      year         = {2020},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, Rheinisch-Westfälische Technische
                      Hochschule Aachen, 2020},
      abstract     = {Micro whistles emit a frequency-coded acoustic signal in
                      the range of ultrasound when mechanically actuated by a
                      bellows, which is outside of the audible range and suitable
                      for the transmission of switching signals, especially for
                      short distances. Micro whistles require neither electronic
                      components nor batteries. The ultrasonic signals are
                      received by microphones. In previous works, micro whistles
                      from thermoplastic polymers have been developed and their
                      application for remote controls has been demonstrated.
                      However, the production of the micro whistles was tedious,
                      because 15 different embossing tools had to be used to
                      produce distinguishable signals by frequency combinations.
                      In addition, the bellows and their attachment to the micro
                      whistles were not firm enough to ensure a working device for
                      a long period of time. Therefore, a reliable use as a signal
                      transmitter was not achieved. Within the scope of the
                      present work, these problems were addressed and resolved
                      with regard to mass production and later use as a partial
                      solution in Ambient Assisted Living systems (AAL).A
                      multi-whistle combining micro whistles with six different
                      frequencies on a polycarbonate chip was developed and
                      manufactured by ultrasonic manufacturing. By closing four of
                      the six single whistles, 15 frequency combinations are set
                      manually. The micro whistles are actuated by bellows made of
                      2-component silicone. The design of the bellow was selected
                      such that the applied force is 7.5 N. To fix the bellows on
                      the pipes, a clamping ring was developed and milled from PC
                      or manufactured by 3Dprinting.This clamping ring was welded
                      onto the chip by ultrasound. The bellow was then inserted
                      into the groove between clamping ring and multi-whistle.
                      Several different bellows were subjected to an endurance
                      test on a pneumatic test stand and their operations until
                      failure were recorded. The bellow used for the multi-whistle
                      failed after 5,200,000 load cycles. To fabricate a large
                      number of multi-whistles for further experiments, an
                      automated system for ultrasonic hot embossing of polymer
                      chips was developed. The system has a modular structure and
                      was mounted onto the ultrasonic welding machine. By the
                      drive of pneumatic cylinders, two joined chips with the
                      dimension121 × 50 × 1 mm³ were pushed from a magazine
                      onto a polymer foil above an embossing tool and fixed there
                      by a clamping frame. After the embossing process, the
                      embossed chip was lifted off the tool, ejected together with
                      the foil by a foil-winding unit and wound up. With the fully
                      automatic operation of the embossing process,
                      70multi-whistles were produced on a 2.5 m long foil section
                      in 10 minutes. To verify the use of multi-whistles as a
                      possible partial solution in AAL-systems, a multi-whistle
                      operated switch has been developed. The switch has a force
                      threshold of 11.9 N caused by magnetic force. This force
                      must be overcome during actuation and, that way, the switch
                      is actuating the multi-whistle with a reproducible pressure
                      difference generating a reproducible signal. In 50
                      measurements of six different whistle combinations, four of
                      the nominal frequency pairs were recorded by 100 $\%.$ Only
                      two combinations of whistles showed a lowest detection rate
                      of 98 $\%.$},
      cin          = {417420},
      ddc          = {620},
      cid          = {$I:(DE-82)417420_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2020-07274},
      url          = {https://publications.rwth-aachen.de/record/793926},
}