In the second version of the PopCAD, we replaced the copper tape with conductive fabric tape, which can be laser cut. We carefully etched out a circuit on paper, cutting through the tape and not the paper underneath to make a circuit stencil. We also used thicker weight paper, a pull-tab pop-up mechanism that eliminated the need to place any paper struts between the paper towers, and replaced all the traditional wires used in the first version with the conductive fabric tape. This version went through over 40 hours of user studies with 11-18 year old kids and still works. Due to the low cost of this device, the plan is to refine the design a bit further and release open-source instructions in the hope that educators will build them and help redefine how children learn 3D modeling skills and how they create for 3D printing.
