Abstract
In this paper, we present a methodology for locating wireless sensors for the use in photoreactors. Photoreactors are, e.g., used to cultivate photosynthetic active microorganisms. For measuring important parameters like, e.g., the temperature inside the reactor, sensors are needed. Wireless locatable floating sensors would enable it to measure the data anywhere inside the reactor and to get a spatial resolution of the registered data. Due to the well defined propagation properties of magnetic fields and the fact that they are not significantly influenced in underwater environments when using low frequencies, a magnetic induction (MI) system is chosen for the data transmission as well as for the localization task. We designed an inductive transmitter and a receiver capable of measuring the magnetic field in every three spatial directions. The transmitting frequency is set at approx. . This results in a wavelength of approx. which clearly exceeds the dimensions of our measurement setup where the transmitter–receiver distances in general are lower than one meter. Due to this fact, only the quasi-static field component has to be considered and the location of the transmitter is calculated by measuring its magnetic field at defined positions and in using the magnetic dipole field equation in order to model its magnetic field geometry. The used measurement setup consists of a transmitter and two receivers. The first measurements were performed without a water filled photoreactor since no differences in the propagation criteria of magnetic fields are expected due to the negligibly low differences in the relative magnetic permeability of water and air. The system is calibrated and validated by using a LIDAR depth camera that is also used to locate the transmitter. The transmitter positions measured with the camera are therefore compared with the inductively measured ones.
Highlights
The internal illumination system based on the wireless light emitters (WLEs) is used to perform photocatalytic reactions; the WLEs are coated by a photocatalyst [6]
We evaluate the magnetic field of the simulated coil for different radial distances around the coil center on a plane defined by the coil axis and the coil radius
The difference between the position coordinates measured with the depth camera and the inductively measured positions are given as ~∆cam−ind, and, consequentially, ~∆cam−calib indicates the differences between the tuned position and the exact position coordinates
Summary
In order to increase the ratio between the illuminated surface and the reactor volume, the used reactors are characterized by small layer thicknesses, which lead to a significant increase in the construction volume [4]. To counteract this issue, a wireless internal illumination for photoreactors has been developed [1]. The internal illumination system based on the WLEs is used to perform photocatalytic reactions; the WLEs are coated by a photocatalyst [6].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
