Magnetic docking stations for remotely powered light emitting diodes

Abstract

Light emitting diodes (LEDs) are efficient light sources which due to low power consumption often are considered for demonstrations of wireless energy transmission. It is often not only necessary to power these light sources wirelessly, but also to ensure that they conveniently dock at the correct position as effortlessly as possible without the need for chemical adhesives or mechanical attachment. In the current work a passive magnetic docking system which aids attachment of wirelessly powered LEDs is proposed. The system utilizes electromagnetic induction of nearby coils to power the LED. The spatial range of the magnetostatic interactions is controlled by the specific magnet arrangement used, such that the light is turned on either before or after docking is initiated. The constant and time-varying magnetic fields occupy the same volume, thus allowing the presenter to demonstrate the difference between magnetostatic interactions locking the LED in place and electromagnetic induction turning the LED on. It is demonstrated that the proposed system works well for light signaling in salt water, and may find use in wireless underwater communication.

Transmission of electromagnetic waves from a plasma globe to a light emitting diode

“…On the other hand, light emitting diodes (LEDs) are small, cheap easy to obtain and can be handed out to each participant in smaller or larger classes. LEDs are sometimes used to illuminate wireless energy transfer using coils [4], and activities presented here may complement such an approach. In the following I discuss some of the activities and questions I have used in my own teaching to small student groups L E Helseth in introductory electromagnetism to initiate discussions on electrical conduction and wireless transfer of electromagnetic waves, using a plasma globe as transmitter and LED as receiver.…”