Electrotactile feedback is a promising solid-state alternative to mechanical actuators for wearable Human-Computer Interaction (HCI) andd Virtual Reality (VR). However, synthesising realistic, comfortable tactile illusions (such as a physical button press) remains challenging due to the fingertip's complex neurophysiology, skin-electrode variability, and multidimensional electrical parameters. Collectively, these factors impose severe calibration burdens and frequently cause irritation rather than intuitive touch.

This thesis addresses these challenges through a systems-engineering methodology spanning hardware development, signal design, and psychophysics. A custom electrotactile platform was engineered alongside multiple candidate electrode geometries, culminating in a co-located "Bullseye" design that strictly confines current density. To navigate the parameter space, a touch-dynamics-driven framework applied a "ramp-hold-release" envelope to generate a library of single-pulse and burst-structured waveforms. To solve the calibration bottleneck, a predictive Energy-Intensity model was formulated to bypass exhaustive manual tuning by mathematically estimating thresholds from a single baseline. Finally, a human-subject study evaluated these waveforms across three progressive tiers of multisensory realism: Tactile-Only, Visual Integration, and Visuo-Motor Integration.

Rigorous mixed-effects modelling yielded several critical insights. First, the hardware and experimental calibration proved highly robust: the Bullseye electrode successfully anchored the tactile percept to the target centre in over 89% of trials, while perceived intensity stayed within a strict tolerance band for 92% of observations. Second, the predictive Energy-Intensity model confirmed Stevens' Power Law (k = 0.893) and demonstrated high explanatory power (R²=95.5%) for estimating participant optimal thresholds from a single known baseline. Third, temporal waveform analysis revealed a psychophysical "penalty of complexity". Temporal modulations-specifically dynamic Amplitude Modulation (OR ≈ 1.59) and Burst Pulse-Count expansion (OR ≈ 1.87)-degraded naturalness and inflated nociceptive irritation. Instead, an unmodulated Low-Frequency baseline emerged as the optimal carrier, drastically reducing irritation odds (OR ≈ 0.16). Finally, congruent Visuo-Motor cues synthesised a pseudo-haptic illusion that enhanced perceived realism (OR ≈ 1.80) and caused the spatial focal point to systematically drift distally, matching internal kinematic expectations.

Ultimately, this thesis demonstrates that the most effective, comfortable electrotactile virtual button is achieved not through complex electrical waveforms, but by pairing a stable, low-frequency baseline with congruent multisensory environments. Bridging hardware innovation, predictive calibration, and cross-modal psychophysics, this work establishes a clear, data-driven engineering directive for the future design of wearable electrotactile interfaces.