Developing advanced tactile sensors is important for cutting-edge applications such as human-machine interaction. However, the current tactile sensing technology primarily exploits triboelectrification, which is inherently susceptible to ambient interference, obstructing their real-world applications. Herein, a robust tactile sensing platform is presented that leverages piezoelectrics for mechano-optoelectronic transduction. A new class of ScBO3:Cr3+ crystals is developed that can produce intense broadband near-infrared light under sole mechanical pressure through self-recoverable mechanoluminescence (ML). Through a combinatorial doping strategy, deliberate modulation of ML profile is achieved across a broad wavelength range with a precision down to ≈1 nm and a full width at half maximum up to ≈273 nm. This effect allows maximal optoelectronic conversion using a basic silicon photodiode free of ambient interference. These findings enable a fast-response (≈20 ms) and low-threshold (≈kPa level) tactile stylus that can accurately authenticate signatures with the aid of machine learning algorithms in complex environments presenting moisture and light interference.