Publikationsserver der RWTH Aachen University
Ultraschallerzeugende Mikrostrukturen für batterielose Fernbedienungen
Abstract
dc:descriptionContemporary wireless remote controls are mostly based on infrared or radio communication technology. Both methods are dependent on electric energy and electronic components, which leads to hazardous waste. While infrared or radio signals can not be produced without elaborate electronic equipment, ultrasound can be produced mechanically with relatively simple components. Therefore it seemed expedient to fall back on ultrasound, which was used in the first wireless remote controls, and to further develop this technology. For this purpose, the sound generation mechanisms of musical instruments were analyzed. Vibrating beams and micro whistles were determined as best applicable for the generation of ultrasound in remote controls. In the main, the generation of ultrasound with micro whistles driven by silicone bellows was analyzed. The foundations for the production of a coded ultrasound keyboard were laid and a prototype with 15 different keys produced. Ultrasonic whistles with 6 different frequencies were manufactured, two of which combined produced a signal. Therefore a signal consists of two sounds with different frequencies, which are generated by pressing a single key. The number of signals can be significantly increased by time coding, which can be realised with simple structural modifications. Hence the development of a wireless keyboard is feasible. The frequencies of the ultrasonic whistles are pressure and temperature dependent and deviate up to 10% from the respective average value. However, faulty signal identification due to pressure or temperature dependency can be eliminated by utilizing the ratio of the two signal frequencies. Furthermore, vibrating beams were employed for ultrasound generation. The main advantages of this method are independence of the frequency from the striking mechanism and low temperature dependency (deviations ca. 0,5%). However, the striking mechanism and the mounting suspension of the beams are elaborate, which lead to rejection of this sound generation mechanism within the scope of this work.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2009
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Gerhardy, Christof
- Contributors dc:contributor
-
- Schomburg, Werner Karl
Subjects
dc:subject × 8Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger