Tactile sensors play a key role in human–machine
interfaces
(HMIs) for augmented and virtual reality, point-of-care devices, and
human–robot collaboration, which show the promise of revolutionizing
our ways of life. Here, we present a sensor (EMTS) that utilizes the
magnetoelastic effect in a soft metamaterial to convert mechanical
pressure into electrical signals. With this unique mechanism, the
proposed EMTS simultaneously possesses self-powering, waterproof,
and compliant features. The soft metamaterial is essentially a porous
magnetoelastomer structure designed based on the Fourier series expansion,
which allows for programmable mechanical response and sensing performance
of the EMTS. Fabricated by simple 3D-printed molds, the EMTS also
holds potential for low-cost production. Particularly, the porous
magnetoelastomer structure comes with selectable buckling instabilities
that can significantly enhance biomechanical-to-electrical energy
conversion. Also, with the embedded magnetic microparticles, the energy-absorbing
performance of the sensor is greatly improved, which is highly beneficial
to HMIs. To pursue practical applications, the EMTSs are further integrated
with two systems as control and perception modules. It is demonstrated
that the EMTS is able to identify different hand gestures to control
a lighting system even in a high-humidity environment. Also, the EMTS
stands out for its superior capability of simultaneous impact perception
and energy absorption in drop tests. Overall, with its compelling
array of features, the presented EMTS gives impetus to multi-sensing
technology and practically enables a variety of HMI applications.