A prototype ultraviolet (UV) photodetector based on photoelectrochemical (PEC) cell from material synthesis up to assembly was demonstrated in this work. Self-organized titanium dioxide (TiO₂) nanotube layers (1 and 5 μm thicknesses) prepared by electrochemical anodization were applied as the sensing layer in the photodetector. A printed circuit board (PCB) platform with physical size of 2 cm × 2 cm was designed to mount the sensing layer. The photodetector system comprised of a sandwich structure can be described as glass/ITO/electrolyte/TiO₂ nanotube layer/Ti/PCB platform. For this system, a low applied voltage of 0.5–1 V was required to drive the photodetector. TiO₂ nanotube layers have shown positive photoresponse in the entire UV spectral region (λ = 250–400 nm, classified as UV-A, B and C). In particular, the highest response with >850 sensitivity, and responsivity of ≈740 mA/W had been achieved by the 5 μm TiO₂ nanotube layer for detection in the UV-A region, and the respective rise and decay time were 0.88 and 1.28 s. This work shows that the sandwich structure PEC cell UV photodetector with TiO₂ nanotube layer as sensing layer is stable, highly sensitive and provides rapid response. Such platform can be potentially applied for other sensing materials as an efficient photodetector.