This thesis presents the studies on developing methods for sensing origami robots (a sub-class of soft robotics) flexible hinge angular positions. Silver nanoparticle sensor patterns are inkjet printed on the flexible structural layers of the hinges, and the angular positions are estimated based on the electrical resistance change of the printed patterns. The main contributions of this thesis are, developing a novel curing/sintering method for flexible electronics after a detailed analysis of the fabrication step of the sensors, and developing a novel bio-inspired angle estimation method by using a compression-tension sensor pair. A compensation mechanism is revealed by using the sensor pairs, and the angle estimation performances for the subject class are advanced substantially. Developed methods are also implemented successfully into the state-of-art origami robots.