Fused filament fabrication (FFF), the printing of parts through the deposition of layers of melted thermoplastic, is one of the most widely used 3D printing processes due to its ease of use, low cost and accessibility. In this work, integration of 3D printed sensors and interconnect between embedded components into a printed part is demonstrated in an FFF process for the first time. The use of printed active materials for sensing allows interactivity with the end user through mechanisms like touch and temperature. Through dual extrusion in a low cost commercial printer, printing of both a conductive thermoplastic composite and a non-conducting filament are combined to create complex patterns. The piezoresistive and thermally responsive properties of the thermoplastic composite are used to create several different sensor modalities including a piezoresistive strain sensor, a contact switch and a resistive temperature sensor. A heated insertion technique is then developed for embedding of electrical components. The conductive thermoplastic is also used to incorporate a 3D printed circuit board in the same part, including in-line embedding within the body of the part during the printing process. The sensor performance and component embedding properties are characterized, and the process is used to print systems including relaxation oscillators and op-amp interface circuits for sensor monitoring.

Herein, complex motion in soft, fluid‐driven actuators composed of elastomer bladders arranged around a neutral plane and connected by slender tubes is demonstrated. Rather than relying on complex feedback control or multiple inputs, the motion is generated with a single pressure input, leveraging viscous flows within the actuator to produce nonuniform pressure between bladders. Using an accurate predictive model coupling with a large deformation Cosserat rod model and low‐Reynolds‐number flow, all dominating dynamic interactions including extension and curvature are captured with two governing equations. Given insights from this model, five design elements are described and demonstrated in practice. By choosing the relative timescales between the solid, fluid, and input pressure cycles, the tip of the actuator can obtain almost any desired trajectory and can be placed anywhere temporarily within its 2D workspace. Finally, the benefits of viscous‐driven soft actuators are showcased in a six‐legged untethered robot able to walk 0.05 body lengths per second. The foundation is laid for a new class of morphologically intelligent, soft robotic actuators that enables complex deformations and multifunctionality without explicit drivers; whereby generating nonuniform pressure distributions, their infinite degrees of freedom can be exploited.

Origami‐based techniques for creating 3D shapes from 2D patterns via folding have moved from the domain of art to practical engineering. Flat sheets are an appealing starting material for the creation of 3D objects because of 1) the ability to efficiently store and ship stacks of sheets, 2) the compatibility of flat surfaces with a variety of patterning processes such as lithography, and 3) the ability to make sheets via high‐throughput manufacturing. Self‐folding is the ability of flat sheets of materials to respond to external stimuli (light, heat, magnetic fields, etc.) and rapidly change shape without human intervention. Herein, the self‐folding of metals is reviewed, which is particularly important for opening up new applications in robotics, medicine, and reconfigurable electronics. These applications rely on the superior thermal, mechanical, and electrical properties of metals compared with polymer alternatives. The field is reviewed from actuation mechanisms and materials to design approaches and common applications of technologies.