The rapid progress in robotics and materials science has driven the innovation of flexible sensors, leading to important developments in wearable technology. These smart sensors, capable of detecting mechanical stimuli such as pressure, deformation, humidity, temperature, and light, find many powerful applications in health, medicine, sports, soft robotics, prosthetics, and human-machine interaction. Here, this thesis explores the design, fabrication, and characterization of a flexible strain sensor based on DLP solvent-free acrylate resin with ion conductivity given by lithium chloride. Utilizing a 3D printing DLP process, various sensor configurations were produced and tested to evaluate their mechanical and electrical response. The sensible layer, electrodes, and shells were studied to determine the optimal setup.