Gecko‐Like Multi‐Directional High‐Power Magneto–Mechano–Electric Energy Harvesters for Self‐Powered, Hundred‐Meter‐Scale LoRa Communication

Magneto-mechano-electric energy harvesting from stray magnetic fields near power infrastructure is a promising approach for autonomous wireless sensor networks. However, state-of-the-art magneto-mechano-electric energy harvesters (MME-EHs) fail to capture multi-directional 50/60 Hz magnetic fields of power infrastructure due to frequency mismatch and unidirectional responsiveness. To break this bottleneck, this study proposes a gecko-like MME-EH that mimics the flexible, symmetrical movement of gecko limbs to achieve coordinated twisting and bending. The centrally symmetric configuration with low clamping loss allows for high magnetic loads and large beam deformation, resulting in high energy output for driving long-distance wireless sensor systems. Under a weak 60 Hz magnetic field ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>H</mml:mi> <mml:mtext>ac</mml:mtext></mml:msub> <mml:annotation>$ H_{\text{ac}}$</mml:annotation></mml:semantics> </mml:math> = 1 Oe), the bio-inspired multi-directional MME-EH generates average power of 12.8, 0.24, 0.15 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>mW</mml:mi> <mml:mi>RMS</mml:mi></mml:msub> <mml:annotation>$\mathrm{mW}_{\mathrm{RMS}}$</mml:annotation></mml:semantics> </mml:math> in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:semantics><mml:mi>x</mml:mi> <mml:annotation>$x$</mml:annotation></mml:semantics> </mml:math> -, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:semantics><mml:mi>y</mml:mi> <mml:annotation>$y$</mml:annotation></mml:semantics> </mml:math> -, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:semantics><mml:mi>z</mml:mi> <mml:annotation>$z$</mml:annotation></mml:semantics> </mml:math> -directions, respectively, representing power output and power density improvements of up to 17.75 and 5 times, respectively, over state-of-the-art results. The application tests show that the proposed harvester can successfully achieve self-powered LoRa communication over 300 meters outdoors, scaling from the conventional meter scale to an unprecedented hundred-meter scale in the MME area. Furthermore, the long-distance operational status monitoring of the transformer is demonstrated by coupling the proposed MME-EH with the LoRa communication system.